## How to tune color frequencies of light using fluidic elastomer grating: an interview with Dr. Raphael Guerrero

Associate Professor Dr. Raphael Guerrero of the Department of Physics of Ateneo de Manila University attends the SPIE Photonics Asia 2014 at Beijing, China.

by Dr. Quirino Sugon Jr

Associate Professor Dr. Raphael Guerrero of the Department of Physics of Ateneo de Manila University and his student Sarah Oliva wrote a paper entitled, “Optical wavelength tuning via actuation of fluidic grating,” which was published last January 23, 2014 in SPIE’s Optical Engineering journal.

A grating is normally a polished metal with grooves similar to what happens when you grate a cheese with a fork, except that your cheese is a polished metal and your fork is much smaller than the width of your hair.  A good example of a grating is a CD (compact disc): the concentric grooves are finely spaced, so that when light strikes the CD, light beams of particular color (frequency) have a preferential option for reflecting in one direction and those of different colors are reflected in another direction.  The result is a rainbow pattern.

But instead of a metal grating, Dr. Guerrero and Sarah used Sylgard 184, an elastomer or elastic polymer, in order to form a replica of a standard metal grating through a cast and mold process.  The elastomer grating bends like rubber but looks transparent like glass.  The authors constructed a hollow cavity with a grating membrane and filled it with water using a syringe.  As the water enters the cavity, the elastomer grating expands, thereby increasing the grating’s groove spacing.  Once this happens, the various colors present in white light are transmitted through the grating differently compared to the unexpanded situation. This mechanism allows us to scan different color frequencies for a fixed light receiver, in the same way we turn the knob of an analog radio in order to tune to the correct AM or FM frequencies of our favorite radio stations.

Below is an interview with Dr. Raphael Guerrero by the Ateneo Physics News.

Dr. Raphael Guerrero with the Statue of Liberty in New York at the background

1. How long did it take you to finish your research?

This is the second paper I was able to publish with Sarah Oliva, one of our recent BS Physics-MSE graduates. She was member of the lab for her two undergraduate theses and we were able to produce two papers.  Her physics thesis was on the development of a fluidic actuation system for an elastomeric grating.  Overall the work took a year for the development of the theory, the collection of appropriate data, and the writing of the paper for the actuation mechanism. We demonstrated how fluid injection can increase the groove spacing in a grating replica, which allows us to change the diffraction angle of laser beams.

During her fifth year thesis for Materials Science Engineering (MSE). we looked at another set of data using an incoherent, broadband light source such as a mercury lamp. That is, instead of using the grating to deflect a laser beam,  we used the grating to select a particular wavelength of the incoherent light source.  This led to the second paper.

Basically, we used the same setup which we used for the coherent (laser) source, but replaced it with an incoherent broadband source. We used fluid injection to scan a range of wavelengths. The first paper on laser scanning was published in Applied Optics. The second on tuning a broadband light source was published in Optical Engineering. We were lucky that we got two papers out of a year of work.

Sarah worked on the theoretical framework.  It was fortunate that she was taking a programming class at that time and she was working on numerical techniques for solving polynomial equations. We needed this polynomial solution technique in order to determine how the radius of curvature changes as a function of injected water volume.

2. Who introduced you to elastomer research?

I was first introduced to elastomer research by Dr. Greg Tangonan.  In 2004 we were able to use soft lithographic techniques for making an elastomer replica of a standard commercial grating out of Sylgard 184 (polydimethylsiloxane). We had the replica sample coated in the City University of Hong Kong and presented the results in the 2004 SPP National Physics Congress in Bohol, Philippines.  That was our first elastomer paper.

After several undergraduate theses. we published our first ISI-indexed paper on elastomeric gratings in 2007.  We needed  three years to collect enough data and develop the necessary techniques.  Our paper was published in Optics Communications.  In that paper, we described the effect of the buckling of the metal layer due to strain applied on the grating.

After another batch of  undergraduate theses, we found an alternative method for actuating the elastomer grating. Previously, we just stretched it with a mechanical holder.  We became aware of how a shape memory alloy returns to its original form after applying heat.  We inserted such an alloy into our elastomer grating and heated the alloy using electric current.  This led to a concave grating.  We presented our results in Applied Optics in 2010.

The Photonics lab has been very successful with the elastomeric grating. The papers on a fluidic actuation mechanism for the elastomeric grating were published in 2012 and 2014.  We even published an education paper in 2008  where we showed how elastomeric gratings can be used for grade school experiments: students can use the grating to see the rainbow pattern of different light sources. In that paper, we marketed the grating for teaching grade school optics. There is no worry about damaging the optics because the elastomer is flexible and inexpensive. Even if you get the elastomer dirty, you could still wash it because it’s a polymer. In total, we’ve published 5 papers about the elastomeric grating.

Dr. Raphael with Darth Vader at Legoland California

3. How many students do you have?

I have two undergraduate students who are about to defend their thesis proposals. I have three undergraduate apprentices who are incoming juniors. I have a graduate student who is also a fellow faculty member, Cindy Cease.  I have four Ph.D. students in the pipeline: we have one student working on fluorescent nanoparticles in solution, two students working on volume holography of Bessel beams, and one student studying chlorophyll -doped elastomers. These four Ph.D. students will hopefully churn out four to five papers in the near future.

4. What are your future plans?

In the short term, I hope to submit two papers. I am currently making major revisions on the theoretical framework for a paper on variable fluorescence output from an electrowetting droplet. Essentially, we have droplet of water doped with rhodamine. We placed the droplet on a dielectric and apply a voltage through a platinum wire.  When we shine UV light on the droplet, it fluoresces yellow-orange, corresponding to a wavelength of 590 nm. We noticed that when we apply the voltage while the UV light is present, the droplet’s shape changes, and we were able to tune the fluorescence to a different wavelength from yellow to green. This has interesting applications in spectroscopy  or commercial displays.

I was able to submit an original manuscript and was asked to do some revisions. I am now working on the appropriate theory to describe the phenomenon. The revised paper should be submitted before the end of the semester. I am also working on a volume holography paper, this time reporting results on the creation of Bessel beams using photorefractive volume holography instead of computer-generated holograms. Reconstructing Bessel beams is important because of their self-healing properties. Currently, I am revising manuscripts for two papers. I am also asking another PhD student to prepare a manuscript as a basis for her dissertation.  So, in a sense, I am sitting on several ISI-indexed papers.

If I survive my teaching load, I would have three papers, with one under review by the end of the semester. That’s my short term plan.

For my long term plan, I am waiting for my project proposal to be approved by DOST. The funding would allow the laboratory to purchase a variable wavelength laser source. With this I would be able to look into other topics. Right now, the immediate application of this laser would be modifying the propagation properties of Bessel beams, so that we can record them via volume holography. This proposal is part of the grant I received as one of the NAST (National Academy of Sciences) awardees last year.

I received the NAST-OYS (Outstanding Young Scientist) award and the NAST-TWAS (The World Academy of Sciences) award for Physics. The NAST-TWAS is the World Academy of Sciences Award for Outstanding Scientists in developing countries. Last year I was nominated for the physics category of NAST-TWAS.  In other years, the award is for Chemistry or Biology or Mathematics.  I got some cash. There is also a plaque from TWAS and trophy from NAST. Each award comes with Php 500,000 research grant . To obtain this grant, you write a proposal. After a review and approval by DOST, I should be able to get half a million from each award–about a million pesos in all.

I have 6 units for my Third Summer Leave. For my first semester after sabbatical leave, I was assigned 18 units for the first semester–Ateneo is trying to get back at me for having a year off! Next semester, my load is a bit lighter.

Dr. Raphael Guerrero at Cedar Point, the “Roller Coaster Capital of the World”, in Sandusky, Ohio

7. What did you do in your sabbatical year.

I was able to write two papers. One paper was published in Optical engineering last January. I also supervised the graduate thesis of Rea Mero, who finished her MS Physics studies this year. Her results were the basis of the second paper I was able to write on tunable fluorescence from an electrowetting droplet. I am now in the revision stage of the second paper. I also supervised a PhD student and helped prepare a manuscript which shall serve as the main part of his dissertation. Finally, I prepared a proposal for DOST to take advantage of my OYS grants.

In addition to academic pursuits, I took a lot of time off to sleep in order to recharge for another six years without a sabbatical leave.  It was a good year.  It’s always a good year when you get published.

8. Where did you go during your Sabbatical Leave?

I spent the first two months of my vacation with my wife and her family in the US. We went everywhere along the West Coast.  We went to theme parks.  We went to Las Vegas–my first time. We then visited my brother in Tennessee. We went to the “roller coaster capital of the world” in Ohio .  I saw this roller coaster on a website and promised myself that I would ride it.  So I made sure to visit that theme park.

My wife and I also went to New York.  We went to the Natural History Museum with all the dinosaurs. We visited the Empire State Building. We visited our friends in Pittsburgh where the Andy Warhol museum can be found.

Last July I was just here, supervising my MS student and writing papers. Every now and then, I would get invited as a speaker or member of a thesis panel. I did a lot of writing and experiments with my students.

My sabbatical leave started April of 2013 and it ended with my third summer leave last May 31, 2014. That was 14 months.  And they went by just like that. It was very sad by the time May came. By June I had to go back to work with 18 units.

9. You teach tutorial classes?

I have two tutorial classes. I have graduate level Quantum Mechanics and Mathematical Methods for Physics Education. I was able to have my experimental graduate class waived. In all, I have 18 units of regular teaching load and 6 units of tutorial classes.  These filled up my schedule.  When one of my students gets results, I need time to sit down with him and think about his data.  It is hard to find time to just think about research when you are teaching or preparing your lectures.

10. Do you have any parting words

I would like to mention how critical it is to have students who turn out to be excellent researchers.  They are a big help to the Photonics lab in particular and to the the Department in general.  I am glad to find students like Sarah Oliva who as undergraduates are able to produce world class results which could be published in journals. I am riding on the shoulders of my students. Of course, in the writing of papers, you still need to help them.  But over all, with the quality of their research and hard work, I feel blessed.

Dr. Raphael Guerrero at the Great Wall of China

## Ateneo Physics Student and BPI-DOST Science Awardee Sarah Jaye C. Oliva wins First Place in the video contest of Optical Society of America

by Quirino Sugon Jr.

After receiving the BPI-DOST Science Award Last 4 March 2013 at Escaler Hall in Ateneo de Manila University for her work on “Optical wavelength tuning using a fluidic grating” under Dr. Raphael Guerrero, BS Physics with Materials Science Student Sarah Jaye C. Oliva won again another award this year. Sarah won First Place in the 1st Annual Enabled by Optics Contest for the Students Category by the Optical Society of America (OSA). According to PRWeb:

Sarah Jaye Oliva, a graduate student at the Ateneo de Manila University in the Philippines, clinched first place in the student contest for her video “Black and White,” which describes the simple, but ingenious product enabled by optics—the laser barcode scanner. The video describes how the technology uses optics and the science of colors to do its valuable job.

Below is an interview with Sarah Oliva by the Ateneo Physics News. The interview on the BPI-DOST Science Award was held last March 20, 2013, while that on the OAS Award was done last November 22, 2013.

Ateneo Physics student Sarah Jaye Oliva during the awarding ceremony for the BPI-DOST Science Award at the Escaler Hall, Ateneo de Manila University, last March 4, 2013.

A. THE BPI-DOST SCIENCE AWARD

Date of interview: November 22, 2013

A grating is an optical element—it is like what you find on the back side of your CD. You notice that when you move the CD around, you see colors around it. That is how the diffraction grating works. The white light is bent at different angles for different colors so you see a rainbow. Our fluidic grating is made of a polymer chamber and inside it is filled with water, in contrast to hard lenses which are made of glass. Our setup allows us to change the properties of the grating by controlling the volume of the water inside. By injecting more liquid into it, the grating gets stretched and effectively changing the grating spacing and how the colors are bent.

Optical wavelength is in the range of hundreds of nanometers. Tuning means I can control what wavelength of light I want as an output. In a sense, it is like tuning a radio: you change the frequency you want to listen to. But in our work, we changed the water volume to change the wavelength output. The wavelength and frequency are inversely related to each other with the speed of light as proportionality constant.

2. Is this idea new?

To the best of our knowledge, tuning using fluidic grating is novel research. There are other studies in related literature using fluidic lenses. There are also others with grating and lens setups, but we haven’t come across research that has a grating and lens in one element. A part of our work was already published in Applied Optics 2012, but only the first part–the variable diffraction part. In this set of experiments, we also use the fluidic grating. We used monochromatic lasers and a white light source for our tuning experiments.

BPI-DOST Science Awardees for 2013. From left to right: Nikita P. Bacalzo, Jr. (BS/MS Chemistry), Sarah Jaye C. Oliva (BS Physics with Materials Science and Engineering), and Napoleon Salvador B. Antonio (BS Chemistry with Materials Science and Engineering)

3. How were you chosen as BPI awardee?

It started when my adviser told me to fill up some forms and prepare a write-up of what I have done so far. This was about October last year. And then as the semester ended, we were called for an oral presentation in front of a panel of judges from different Ateneo departments. By then they had narrowed down the list to six finalists. There were six of us who did the oral presentation. After that the judges and the SOSE (School of Science and Engineering) dean narrowed down the list further and chose the three finalists of the Ateneo. Each school from the ten partner schools of the DOST chooses three finalists. From this pool of 30 students, BPI-DOST shortlists six who shall compete for the project of the year award; the 30 of them already get the BPI-DOST awards. The six do another oral presentation for the project of the year award in in addition to the science award. I did not make it to the topi 6. It was Napoleon Salvador Antonio of Chemistry who made it to the Top 6.

4. Is it true that you only shifted to physics?

I started college as a BS in Applied Mathematical Major in Mathematical Finance (AMF). After a year of discerning, I decided to shift to physics. Even though I love math, I am not into business related things and essentially that is where AMF seems to be directed to. i decided that i want to pursue science. It is a childhood thing. All the science books and discovery shows sparked my interest as a kid. And out of the different sciences it was physics that I really got interested the most because of my physics high school teacher who taught it well. I am from St. Joseph’s School in Naga City in Bicol. It is a small Filipino-Chinese school. My physics teacher is Mr. Jodel Maomay. And so I shifted. By second year, i was officially a physics student.

5. You met some Ateneo Physics department before you shifted?

I met my physics teachers after I already shifted. I talked to Dr. Benjamin Chan. But before that I talked to upper class physics majors for some of them are my org mates. They were encouraging. They wanted me to get in.

6. I see that your mother came all the way here. How long does it take to go here from Bicol?

It is only an hour by plane and about eight hours on the road—sometimes extended a little bit to ten hours. I am the eldest of three girls.

7. Any parting words?

Looking back, I remembered how scared I was to shift out of the AMF program and into a world of the unknown. I knew a lot of people from AMF, but not in Physics. It was a new thing to me, considering that I only met Physics in the last year of high school, unlike Math which I took since way back. But I am glad I took a leap of faith to pursue what I wanted. Physics is difficult. I knew this before I shifted, but I know I love it. I have the motivation to persevere in this field and do my best here despite the challenge.

Congratulations to Ateneo Physics Student Sarah Oliva for winning the 1st Annual Enabled by Optics Contest of the Optical Society of America for the Student Category.

B. OPTICAL SOCIETY OF AMERICA (OSA) AWARD

Date of Interview: November 22, 2013

1. How did you know about the contest?

I am a member of the Optical Society of America. So I receive the member newsletter. That is where I read about it. There was another video contest a year ago which I also planned to join. Since I let it pass last year, I thought I might as well do it this time around. I made it happen.

2. Who thought about the concept?

Me. My boss (Dr. Raphael Guerrero) didn’t know about it until the results came out. It was Summer. He was out of the country that time. I did it on my own.

3. How did you know that you won?

They informed me by email, but I can’t remember when that was. I think that was about three months after the contest closed. At first, I was unbelieving, because I don’t know the email address. It could be anyone. They told me that they unanimously chose my entry. I was shocked. At that time I already forgot about it. I thought I didn’t win. And they told me to not share the news first. They wanted to announce it properly when the time came. So I didn’t tell anyone about it until they publicized it. That was when I told Sir Guerrero and that was when he learned about it.

4. Did you go to the US for the awarding?

I was not able to go. They invited me to come over for the awarding. But the awarding was right in the middle of the exam week first semester. So I told them I cant. There are also other problems: I don’t have a visa and stuff like that.

5. Is there a cash award?

There should be. I haven’t received it because just last week, I think, they had me answer some forms for the release of the check.

6. Can you summarize what you did in your work?

In my work, I can’t remember the actual phrasing of the theme. It is like how optics is at work in everyday life. And I chose to explain how a barcode scanner works. I explained it by relating it to what people know. So I related it to the common perception on clothes. How white clothes are cooler than darker colored clothes which I related to heat. And from there, it is quite a leap, I explained that the barcode scanner, at the very fundamental level, works in the same way as that. Light or heat (either way) is absorbed by dark colors and reflected by light colors, which forms a wave that is read by the computers. That is how the barcode information gets transferred to a computer. That is pretty much it. I think I won because I kept it simple. The other videos were too technical for me. I think that whole point of the video contest is to explain optics and science to non-science people. That is why I related it to what people experience.

Actually, the original instruction in the contest was to take apart a common item and explain how it works. But I don’t have a barcode scanner to take apart. That is why I did the drawing. At the end of the day, I also decided that drawing would appeal more to non-science people than to an actual video of something. In the video there there are many things going on. There is the background and there is you speaking . It is easier to direct people’s attention when you are drawing. And when I did that video, it was just my second stop motion video. The first one I did a week before. As you can see from the video. It is still a little rusty.

Ateneo Physics Student Sarah Jaye Oliva gives a lecture on her work on optical wavelength tuning with fluidic grating.  This work, which awarded for her the BPI-DOST Science Award, was published in Applied Optics 2012, a journal of the Optical Society of America (OSA).

7. What software did you use?

Software! I used Windows Live Movie Maker. Freeware. I used movie maker plus my video with my phone, an iPhone.

8. How long did it take you to make those videos?

I spent an afternoon drawing and taking the photos. And then an evening editing them. I actually did it fast. I did it in one run, one take in everything. I was lazy to take retakes. A day before the deadline, I already had the plan. I could see the plan and how I would do it in my head. I had a plan for several weeks already, but I executed it at the last minute.

9. You read a script or did you just explain as you go along?

By the script. I recorded it separately after I did the editing. I recorded the audio on top of it.

10. Are there other video contests you are planning to work on?

No. I haven’t heard of any other contests. I think I was just lucky that time because of the very rough editing and rough medium. It was lucky to have won that. I’ll try again next year.

11. Are you making more videos now?

No. I stopped there. I haven’t done other videos after that nor am I thinking of doing of something like that. It is actually challenging. It looks easy to do, but it is not, because I really thought of what device to explain and how I can relate that to people. And the easiest way is to visually explain it. There was a lot of planning into it in my head. It never materialized until the last moment.

12. Maybe you have a knack for teaching?

Actually, it got me to thinking when I finished. I always think of teaching as something we know. You teach when you relate it to something your students already know. I never really got to think of it more seriously until I did this video. For one, I appreciate teachers who were able to teach that way. And somehow I am thinking about maybe I can do that, too. I don’t know. Maybe.

13. Are you taking graduate school right now?

No, sir. Fifth year MSE (Materials Science Engineering).

14. How are your career plans?

Grad school. Not sure where. Abroad if I get a good scholarship. Hopefully.

15. Any parting thoughts?

Just go for it. I had that regret last year. I didn’t join the video contest that was held last year. When I saw the entries afterward, there were too few who joined. I was thinking: I can top that. I can do better than that. And then this year I was a little scared. When I submitted the video, I didn’t look at the other videos. I just submitted. I might lose faith. When the contest was over, I looked over the other entries. There were so many of them. What is my chance? And I am the only one who did the drawing. Everyone had real devices with them. So I really thought I did not have a chance. I think just go for it.

## Ateneo Physics faculty Artoni Ang went to a two-week internship at NAIST

by Quirino Sugon Jr.

Artoni Ang setting up of the UHV SEM for Auger Electron Spectroscopy

Artoni Ang, an Assistant Instructor and a graduate student of the Department of Physics of Ateneo de Manila University, went to Narra Institute of Technology (NAIST) last October 2012 for a two-week internship.  NAIST is a graduate school for Material Science, Information Science and Biological Sciences in Nara, Japan. Since 2006, it has been holding the NAIST Project for Interns (NAPI) where qualified students from the Ateneo de Manila University are invited to the laboratory of their choice for a 2 week internship.  For his internship, Artoni went to the Surface and Materials Laboratory under Professor Hiroshi Daimon.  This laboratory focuses on the study of nanomaterials, surfaces, and interfaces using the 10 m long Ultra High Vacuum (UHV) total analysis system developed by the laboratory.

Below is an interview of Artoni by the Ateneo Physics News:

1. How long have you been teaching in Ateneo?

Less than a year.  This is my second semester. I am teaching Ps 1 and 2 (Natural Science course) and various lab classes for Health Science and Biology majors. I am teaching 13 units this semester.

2.  Where do you do your research in Ateneo?

I work in Mr. Ivan Culaba’s Vacuum Coating Laboratory at the first floor of Faura Hall. Right now I am working on thin films on elastomeric substrates. I am trying to make stretchable diffraction grating. Specifically, I wish to reduce the cracking on the metal film as the grating is stretched. Metal films on stretchable substrates have many applications.  Diffraction gratings are just one of them.  Diffraction gratings are surfaces with very fine line grooves like furrows in a field, except that the distance between furrows is in the order of the wavelength of light, which is a few hundred nanometers or a fraction of the width of a hair strand.  Reducing cracking of the grating would increase the lifetime of such material.  I am working on the optical properties of materials by using the grating as a beam scanner. If we have a beam incident to the grating, we can change the angle of the of the reflected beam by stretching the grating. Stretching would change of the grating pitch or the distance between the line grooves.

3.  How is your work in the lab related to your work in the NAIST laboratory?

It is not exactly related but similar . Here we work with thin films with thickness levels in the nanometer and micrometer range in the wavelength of light. In NAIST we work with even thinner films in the Angstrom level or about 10 layers of atoms thick. Here we have high vacuum systems with pressures of $10^{-5}$ torr. In NAIST they have ultra high vacuum high systems of $10^{-10}$ torr. Most of the procedures in running the equipment are the same, except when the pressures reach $10^{-10}$: they have to bake the chambers. They wrap the chambers with heating blankets and bake the chambers for a month to get it to $10^{-10}$ torr. In our case to reach $10^{-5}$ torr, we only need 2 hours to pump it down. We use rotary pump and oil diffusion pump. In NAIST they use turbo molecular pumps and titanium sublimation pumps. After they bake their chambers they leave it at that pressure range. Then they leave all their pumps turned on 24 hours a day. In our case, we shut the system down once we are done with a specific experiment. We don’t need to keep it turned it overnight, because we can regain the same pressure the next day after 2 hours.

The panel that controls the substrate holders in their UHV system

3.  How many interns were from Ateneo?

There were 10 of us: 1 from Biology, 4 from Materials Science, and 5 from Information Science. I am part of the Material Science group. We were all assigned to different labs. We only see each other during scheduled trips or if we run into each other during the day. I am on my own from 9:00 a.m. to 5:00 p.m.

4.  What was your day like in the NAIST laboratory?

During my first day there, they held a welcoming tea party for me. So all of the grad students and most of the pofessors were there. I get to meet everyone. Since they were around 20 of them, I can’ t remember all their names. They opened the dried mangoes I brought. They all liked it. It wasn’t a formal Japanese tea ceremony.

I was there for 2 weeks. But lab work was only about 8 days. The usual day starts with me going to the laboratory at around 9:00 a.m, though I usually try to arrive a bit later. I don’t like to be the first one in the laboratory alone. And I stay outside to wait for a graduate student to arrive. They actually they told me where they hide the key, but I am not comfortable going inside without them. My day actually starts around 10:00 a.m. I waste an hour waiting outside.

Their lab is divided into two main parts: experimental section and the offices. In my  first day they assigned  me to an empty desk. And that is where I stay. In my first day, too, I met with one of the professors: Sakura Takeda-sensei. She created a schedule for me so that I will be working with different students with their own research projects. When working with them, they perform their experiments and explain the details to me. And in some cases. I get hands-on. In one particular case, we were working for two days on a scanning tunneling microscope. But it was repair and maintenance duties. We have to remove some of the main components. It was a long job. I think they finished all the maintenance work a few days before I left. And they started baking it. I guess they had to wait a month before they can even start using it.

I was assigned to do analysis on the data we collected in the experiments. I did image processing on diffraction patterns from RHEED (Reflection High Energy Electron Diffraction) experiments. I analyzed the data collected using ARPES (Angle Resolved Photoelectron Spectroscopy). From that data we were able to obtain the electron band structure of the Lead monolayer on Germanium. I was  suppose to get the mass of heavy hole from that data, but I did not get to finish the calculations. They had their own software which came with equipment. And there was another software that I think one of the graduate students wrote using java. It just converts the data collected from ARPES to electron band diagram we are all familiar with.

I worked with another student doing RHEED experiments on Indium monolayer on Silicon substrates. I also used the Scanning Electron Microscopes on Iron polycrystalline sample. I was suppose to help on the experiment involving Bismuth on Silicon, but one of the major gauges broke down, so we have to stop.

I attended study sessions, a laboratory meeting, and a laboratory colloquium. In the study session, we spent around an hour discussing theoretical principles behind ARPES. In the colloquium, we spent the entire morning listening to two graduate students presenting papers relevant to their work. It would have been were more interesting if they were reporting in English, but they were speaking in Japanese. I sat there the entire morning looking at their slides. In the afternoon is the colloquium where every graduate student presented a slide or two about their progress since the last lab meeting. Some of the students were presenting slides whose only progress is that  they attended courses or studied their exam. Nevertheless, they still have to present those because it is apart of their process. There are also students who made a lot of progress. They presented a lot of the data they were collecting. They also made me present a brief overview of the research that I do in the Philippines. I had to leave after 4 hours. I think their meeting lasted 6 hours–the whole afternoon. Between the colloquium and laboratory meeting is lunch break. And there is 30 minutes of general laboratory cleanup.  Everybody cleans by sweeping or mopping the floors.

During the first week my sensei gave me a lot of books. After 5:00 p.m. , I usually go straight to the dorm and read the books–not the entire book but only the selected chapters. I think she was surprised that I can read them overnight, because she is just used that her students have difficulty reading books in English. So from their point of view, I read really fast.

A group photo with the professors and students of the Surface and Material Science Laboratory

5.  What do you like best during your stay in Japan?

Their transportation system is very organized. If the train is scheduled to arrive at 8:02 a.m., it will actually arrive at 8:02 a.m..  So if we go out for dinner or cultural trip, our entire travel itinerary was already arranged, because they know the schedules of the trains and buses. It was easy getting around even without a car.  And this was in Narra which is not one of the big urbanized area. But despite that the transportation system is very good. In fact when you go out to the gate of NAIST, the first thing that you see is a rice field and it smells like a rice field. But then there is a bus station in front of the gate.  So even if it is in the rural part of Narra, we can still get around. We can also actually walk to the closest train station, but it takes 40 minutes.

It seems very safe there. There were times we walked to the train station in the middle of the night beside the big mall at around 10 or 11 p.m. We were not worried about being held up. The sense of security is also visible in the campus itself. They don’t have a close gate. It is just an open road that goes toward the campus. I don’t see any security guard walking around.

Of course the food was great. The organizers brought us to Japanese restaurants. We got to try sushi, yakiniku, okonomiyaki, ramen, and some other Japanese foods. Before I went there, I promised myself that I will never say no. I will eat whatever served to me. Half of what I ate there, I don’t know what it was. And then we had weekend trips to Kyoto, Osaka, and Narra. We got to visit some of the old temples and an aquarium in Osaka. During our last day there, they took us to the shopping district in Osaka,where they sold everything from electronics to anime things to clothes.

6.  Any parting thoughts?

Overall it was a good experience. You get to see how research is done in universities in other countries. The research culture is very different. Most of the students are full-time researchers. They don’t attend courses. They only worry about their research projects. They spend an entire day in the lab, because they have a desk there. They are really focused on what they are doing in the lab. Unlike in my experience as a student, my attention is divided in the courses I am taking and the research I am doing. Of course, it would be easier if you are only focused on research work.

It was also eye-opening to me to see how disciplined the Japanese people are.  After eating in the cafeteria, they clean up. We don’t see people littering. They all follow traffic rules, unlike here in the Philippines where traffic is very chaotic.

After I finish my Masters degree, I plan to apply for Ph.D. degree outside the Philippines. I am now looking at Erasmus Mundus program for Materials Science. I have already informed my Professors in NAIST that I will be applying there, too. Hopefully, I get accepted to one of them. If not , I shall also apply to universities in the United States.

## Old solar films from the Solar Building were transferred to Manila Observatory’s Archives

by Quirino Sugon Jr.

Rafael Joseph del Mundo of Manila Observatory's Library and Archives

Last week, I visited the Manila Observatory’s Library and Archives and met with  Mr. Rafael Joseph del Mundo, the Observatory’s new librarian.  Raf is from the Ateneo Library.  He replaced Ms. Carina Sarmaniego who transferred to the Ateneo de Manila University’s Archives.

“Hi, Raf,” I said as I walked through the door.  “Nino Uy said that some films from the Solar Building were transferred here.  Would you know where they are?”

“Yes,” he said, “It’s on the other side.”

We went to the room at the back of his office.  I looked around.  There are rows and rows of shelves containing long sheets of paper, some of them showing signs of termite infestation.  These were from the seismic vault at the center of the Manila Observatory complex.  I saw these sheets years ago as they were transferred in boxes from the vault.  The sheets now rests on the Archives, awaiting the day when a scientist would pore over them, looking signs for small tremors that can only be measured by these delicate instruments: the pulsations of the earth due to the moon or the water waves beating on land.  The Archives used to be the Jesuit kitchen.  But the Jesuits are gone.

“Where are the solar films?” I asked.

“Its outside the door,” Raf said, pointing to the exit.

We walked towards the door and opened it.  And I saw the the long hallway of the third floor of the Observatory’s Main Building.  Non-Jesuits were forbidden here before.  The nearest room is the sacristy.  Behind the wooden walls are three side chapels for private masses with altars fixed to the wall.  There are still still old chasubles there of different colors–gold, black, red, green, and violet–all collecting dust for decades.  The next room is the chapel.  Through the wooden slitted walls you can see an empty room with the other wall filled with windows which give a good view of the green fields and blue skies. A large crucifix hangs above a small altar table.  The tabernacle’s red light is lit.  The other rooms are Jesuit lodgings.  On each door is a slit for mails.  There is one common toilet with several cubicles.  I heard that these lodgings would soon be gone and replaced with research laboratories for students and scientists of Ateneo de Manila University and Manila Observatory.  The farthest end of the hallway is shrouded in darkness, but there is a stairway there that leads to the lower floor and another stairway that leads to rooftop for watching the stars at night.

“So Raf, where are the Solar films?” I asked.

“It’s behind the door,” said Raf.

Behind the door is a gray metal cabinet, about an inch shorter than my shoulder height. There are 10 vertical layers and each layer has 5 drawers.  I read the labels:

• Razdow processed film: 1968 to 1979
• Photographic journal of the sun: Dec 1967 to Feb 1978
• White light: 1963, 1975-1978
• Sunspots: 1974-1975

Jesuits at Manila Observatory in 1956: Fr. Doucette, Fr. Deppermann, Fr. Miller, and Fr. Hennessey

The Razdow 10 inch refracting telescope was set up in 1968 on top of the solar building.  From the base to the tip of the objective lens is about two and a half persons high, and the telescope’s diameter can fit a small boy.  Razdow telescopes were designed by Dr. Adolph Razdow for tracking the sun across the sky and transmitting images of the solar disk in the Hydrogen-alpha spectrum.  Fr. James J. Hennessey, SJ described the Razdow telescope in 1969:

The Razdow refractor (Figure 3) makes use of a Halle filter to obtain the solar image in hydrogen-alpha light.  The sunlight beams is divided and fed into four different systems: (a) to the eye piece for detailed visual patrol, (b) to the camera for thirty-five millimeter recording at preselected rates usuallyu one photo every minute, (c) to the photocell for keeping the objective tracking the sun and (d) for the television pickup.  This last system presents a large image of the sun for convenient monitoring of solar activity.  In such a preceision in instrument it is evident that other worthwhile features have been built in, for example, the automatic sunset stop and return to sunrise position, the automatic camera exposure mechanism, humidity controls, and a set of occulting cones for prominence photography. (Solar Physics 9 (1969) 496-501)
Fr. James J. Hennessey, S.J. (1909-1987) joined the Manila Observatory 1951 and succeeded Charles E. Deppermann (1889-1957) as director in 1957. (Udias 2003, p. 156)
The Razdow telescope was actually used in conjunction with the spectroheliograph.  This was also described by Fr. Hennessey, SJ in the same paper:
In 1963 the first major solar instrument put in operation at this site was the vacuum spectroheliograph.  This was specially designed for Manila.  A pair of 16-inch coelestat mirrors directs sunlight to the 12-inch objective mirror of an off-axis Gregorian system with a choice of either 8-inch or a 3-inch secondary mirror.  All optics are of fused quartz.  The entrance slit of the vacuum tanks serves dual function.  Part of the light beam is reflected to a Halle Lyot-type filter.  This passes only $H\alpha$ light needed for the visual patrol and for photography.  Secondly, the light beam entering the slit passes to an off-axis 11-inch parabolic mirror at the bottom of the 17-foot vacuum tank, then to the Bausch and Lomb replica diffraction grating.  From the six-by-eight-inch grating with 15000 lines to the inch, the selected spectral light is reflected down the tank to a second off-axis 11-inch parabolic mirror and thence to the exit slit at the top of the tank.  The seals at the entrance and exit slits are similar field lenses.  This system can be used either as a spectroheliograph or as a spectrograph.  In daily routine use hydrogen and calcium spectroheliograms are taken.  The Halle filter serves well for the monitoring  of solar features. (Solar Physics 9 (1969) 496-501)

A more detailed description of the spectroheliograph is given by Fr. Richard A. Miller, SJ in Applied Optics 4(9), pp. 1085-1085 (1965).  Fr. Richard A. Miller (1917-1974) came to the Observatory in 1957. He studied at Fordham University and University of Michigan (Udias 2003, p. 156).

The spectroheliograph’s celeostat was disassembled a few months ago and stored to another area (see pictures of the disassembly here).  The Solar Building will be renovated to house the research programs of the Observatory which will be transferred from the Main Building.  With the dismantling of the spectroheliograph, an era has ended.

Solar films from the spectroheliograph

I pulled out some drawers and took pictures.  I saw the 35-mm films, coiled as big as my palm.  These were the standard for high definition photography before and even until now, though some movie makers and advertisers are now shifting to HD (high-definition) digital cameras.  I tried to unroll the film, but some parts are stuck to each other.  The pictures have deteriorated.

“How do you clean this thing?” I asked.

“Using dry method,” said Raf.  “You just wipe it with dry cloth.”

“I think these things need to be placed in airconditioned room in order to prevent their further deterioration,” I said.

“No, we can’t do that,” said Raf.  “The chemicals in the film have fermented.  The vinegar will evaporate and destroy the other documents in the Archives.  I am thinking of sending them to the Ateneo Library to have them digitally scanned or photographed.  That’s all that we can do.”

I pulled another drawer.  I saw a piece of glass with grid lines inside a circle.

“Oh, cool!” I said.

“I think this is used to locate the positions of the sunspots, where they are on the sun,” said I.  “Look, here’s another one,” I said as I picked up a glass plate with globe-like gridlines.  “I think this is used for determining the location of the sunspots in solar longitude and latitude.”

“There are still other pictures here,” said Raf, as he pointed to a box outside the cabinet.

They are large black-and-white pictures of the sun as big as my fist.  I can see the swirls and spots on the sun’s surface like storms on the earth.  If the sun is very magnetically active, there are more sunspots.  The plasma is made of up charges moving around the sun’s magnetic fields.  These magnetic fields guide the paths of the charges, specially during solar flares and prominences, when parts of the sun erupts like a volcano.  An active sun with many sunspots means the earth becomes warmer.  Years with very few sunspots resulted to the cooling of the earth, as what happened in 1645 to 1715 during the Maunder Minimum when Europe and North America experienced bitterly cold winters in the Little Ice Age.

I thanked Raf for his time and we went back to his office.  After taking his picture, we parted and I went down to the Manila Observatory’s lobby.  Outside the afternoon sun still shines.

Solar rectangular grid

Solar grid in spherical coordinates showing longitude and latitude lines

H-alpha patterns and structures used for inferring magnetic polarities in the sun's surface

Photograph enlarged from patrol filtergram obtained by the NOAA-operated NASA Solar Particle Alert Network observatory in Boulder, Colarado, on June 18, 1968. Inferred neutral lines and polarities are indicated below.

A picture of the sun

An image of the sun using calcium spectral line filter

## Dr. Raphael Guerrero of the Ateneo Photonics Laboratory presents a paper in the 2010 SPIE Optics and Photonics Conference in San Diego, California

Dr. Raphael Guerrero attended the conference on “Polymer Optics Design, Fabrication, and Materials II” at SPIE Optics and Photonics Conference in San Diego, California last Aug 1 to 5, 2010. The venue was the San Diego Convention Center.

SPIE is the international society for optics and photonics founded in 1955 to advance light-based technologies. The society has 180,000 constituents from 168 countries. The Society advances emerging technologies through interdisciplinary information exchange, continuing education, publications, patent precedent, and career and professional growth. Every year, SPIE organizes and sponsors approximately 25 major technical forums, exhibitions, and education programs in North America, Europe, Asia, and the South Pacific.

The title of Dr. Guerrero’s talk is ” Beam scanning and color display with an elastomeric grating actuated by a shape memory alloy”, which was co-authored with Michelle Sze and Joby Batiller, both alumni of the Photonics Laboratory. In their work, Dr. Guerrero’s team fabricated a tunable diffraction grating by embedding a nitinol wire within an
elastomeric grating replica. A diffraction grating is parallel series of linear grooves etched on a surface. If this structure is closely spaced enough, as in compact discs, a rainbow of colors gets reflected from the surface. But instead of metal compact discs, they used an elastomer, a polymer used in waterproofing paints and water sealants. To change the the curvature of the grating, they heat the wire inside the polymer, making the wire increase in length due to thermal expansion. By changing the curvature of the grating, they were able to change the direction of the diffracted beam. With 2.0 A of applied current, the 1st-order beam sweeps a diffraction angle range of 15.8 deg in approximately 40 seconds. This technology shows promise in the use of selective color displays.

The Ateneo Photonics Laboratory now has two ISI papers for 2010:

R. A. Guerrero, M. W. C. Sze, and J. R. A. Batiller, “Deformable curvature and beam scanning with an elastomeric concave grating actuated by a shape memory alloy,” Applied Optics V49 N19, 3634-3639 (2010).

R. A. Guerrero and E.B. Aranas, ?Diffraction from relief gratings on a biomimetic elastomer cast,? Mater. Sci. Eng. C, http://dx.doi.org/10.1016/j.msec.2010.06.017 (article in press).

Here are some pictures of Dr. Guerrero:

Fig. 1.  Dr. Guerrero discussing the research efforts of the Ateneo Photonics Laboratory on elastomeric optics.  The photo is courtesy of Dr. Vincent Daria.

Fig. 2.  In the conference, Dr. Guerrero (left) had lunch with Dr. Vincent Daria (center) of University of the Philippines and Dr. Minella Alarcon (right), the former chair of the Ateneo Physics Department and the head of UNESCO’s Active Learning in Optics and Photonics Project which recently got an award from SPIE.

Fig. 3.  After the SPIE conference, Dr. Guerrero visited the San Diego Zoo.  Dr. Guerrero had a great time in San Diego.