Visting OSA Student chapters!

As an OSA Ambassador in the centenanial year for OSA I had the privilege of visiting student chapters in India. In this post I want to record my impressions of that visit.

I traversed from north India (New Delhi, the capital city) to the Eastern cost (Hyderabad) and then Kolkatta before retracing my steps. Each of the flights I took within India was fully 2 hours at the least and the size of the country reminded me that visiting several chapters really needs several days in addition to the actual visits. Not to mention the heat which was beginning to really turn on as the Indian summer got underway (think temperatures of 46 degrees Celsius in Delhi).IMG_1026

The heat, the long flights and hectic schedules were however almost forgotten when interacting with the chapters, being overwhelmed by their generous hospitality and impressed by their work. The passion and enthusiasm that I saw in the students was so infectious and energizing that I feel grateful I could interact with these wonderful students.

In Delhi I met the IIT Delhi student chapter and gave a talk to an audience of 30. There were plenty of questions about the Finite Element method and its implementation, how to deal with field continuity across boundaries and taking care of reflections. On the chapter side the discussion revolved around the best way to engage more of the members in organizing activities and participation.

The IIT Delhi student chapter told me about their activities: seminar series, open days where schools student would visit and be shown demonstrations, quiz competitions and a very successful IONS conference as well. It all sounded wonderful and I was very pleased for a personal reason: I had started this chapter way back in 2003 as a PhD student. So to me the sustained success of the chapter is very satisfying.

This was something we talked about too: when chapter leaders complete their degrees and move on, how to hand over the leadership so there is a continuity in the activities. Good communication was seen to be key! As well as learning from the success stories of other chapters globally to get ideas for events . The chapter was vibrant, active and engaged.

Having thoroughly enjoyed the visit to my alma mater I then hopped to Hyderabad. The Vidya Jyothi Institute of Technology chapter was my host in this historic city which serves the best biryani ever.

I cannot describe adequately how deep an impression the chapter has left on me. Sitting in the outskirts of Hyderabad, the chapter is hosted in a largely undergraduate institution, with some very keen and intelligent students. The chapter was holding seminars and doing some invaluable outreach work going to poor schools and even orphanages, bringing Optics and Science to underprivileged children who would not otherwise ever have access to things like the OSA discovery kit. They are inspiring children who have little opportunity and really brining to life the mission and vision of OSA in a way that deserves recognition and support. I only wish more chapters in India, Asia and Africa would go to schools in poorer neighbourhoods.

Our discussions were ofcourse not confined only to their activities but also the interests of the chapter members! Again the enthusiasm for Science and the love for different aspects of science was like a current running through the room.  Beyond Optics, I was trying to answer questions about black holes and the Large Hadron Collider!

Carrying with me the fantastic experience of Delhi and Hyderabad it was fitting that I went to Kolkatta, the city where Optics was born in India. It is also the city where some of the best sweets are made!

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In a series of joint events hosted by University of Calcutta, IIT Kharagpur, Institute of engineering and Management, that lasted the entire day i met more than a 100 students!

The morning lecture was the University Of Calcutta after which we shared a bus, several cars to go to the Institute of Engineering and Management for lunch and the second lecture, followed by a interaction only session at the University of Engineering and Management.

 

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To say I was overwhelmed by the brilliance of the students, their ideas, their questions and their interest, would be an understatement. If someone could bottle the energy in the room, they could power a city for a week!

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From solar cell optimization, to whether optical computers would be viable to grapheme waveguides the technical discussion was wideranging. The chapters and their activities again were very diverse and there was a real interest from the students in getting new ideas for events.

To each of the chapters, the members, the organisers and faculty advisors I cannot say “thank you” enough times. I loved this experience and I only wish I could have spent more time at each place.

Some common themes that I picked up from all the chapters were:

  • looking for new ideas for events/engaging members. In my view learning from the success and best practice of chapters the world over is a great way to do this. As is engaging with other local chapters
  • paying the OSA memberhip fees via credit cards was not easy for some chapters, and I have since learned that local bodies such as Optical Society of India (OSI) can collect the OSA dues if members also join OSI.

When I set out from London, I wondered how the trip would pan out. Now that I am back I know this: I want to go again!!

A marriage made in CLEO: astronomy/physics and photonics

My love for the stars is not new to some of you. So the tone of this post should not be a surprise.

At CLEO amongst other talks and sessions was a special symposium on

Advances and opportunities in Astro Photonics, JF1N. There were two particular talks that really caught my attention:

The first invited talk (JF1N.1) was by Olivier Guyon titled, “Where are our closest neighbours? Looking for life in nearby exo-planets”.

Exo-planets! Do you need to say even one word more to catch the interest of the people? For sure I was hooked by the title alone and the talk delivered. Some interesting facts that was thrown up in the talk included that about 10% of stars have potentially habitable planets around them. By habitable we mean a mass similar to the Earth and distance that is similar to the Earth from the sun, placing these planets in the habitable zone because that temperature would allow life and may enable liquid water to exist on the planet surface as well.

As the speaker pointed out the question is not if there is life out there but how close it is to us so we know where to look so we know where to look.

He then went on to talk about diff to talk different planet detection techniques: those that are indirect such as astrometry and radial velocity based and those that are direct.

The trouble with direct detection via telescopes on Earth is that the planets are so close to the star (angular separation over this huge distance is very small) that the light from the star far outshines the light reflected by the planet making it virtually invisible. This means we need other more clever ways of finding planets which obviously do not emit their own light.

Radial velocity has thus far been the most successful indirect technique in detecting exoplanets. It relies on the fact that a star also feels the gravitational tug of the planet/s orbiting it and executes motion along an orbit. The change (blue/red) shift of its spectral lines due to the Doppler effect in this orbital motion can be used to detect the presence of the exoplanet.

This technique would detect large planets close to the star in a short orbit, causing a wobble that is detectable. But such large planets close to the star are unlikey to host life. So other techniques are needed to detect smaller planets in the habitable zone.

Astrometry the second technique discussed is where photonics will come in! The technique  relies on the motion of the star changing (a slight wobble if we plot the  projection of its motion around its centre of mass) and detecting this wobble. This would be of the order of a few micro arc seconds while ground based telescopes have detection capability of say half an arcsecond. Theoretically increasing the diameter of a telescope would make it capable of measuring smaller wobbles, but atmospheric turbulence decreases this. Use of adaptive optics is one way to combat it! As well as use of interference with astrometry in the VLTI.

I will blog about the second talk another day. Meanwhile happy reading on astrometry and astrophotonics!!

By artiagrawal Posted in General

Black Phosphorous and other things at CLEO 16

So I am back at CLEO for the third time teaching my short course on Finite Element Method again.

I had a busy 3.5 hours with the course, interacting with about 20 attendees who came to the course. It was much fun and afterwards I had two very interesting conversations on applying numerical methods:

  • what is the best method to use (BPM or FDTD) to study propagation and scattering in media with subwavelength disorder?
  • in highly dispersive materials close to epsillon being 0 (so resonances are present) how does one study non-linear effects in periodic structures where feature shape and size are important?

These sort of discussions are so exciting because they open my mind to new areas and challenge me to think about applying my knowledge and expertise in ways.

But that was not all. 

In talks I attended an invited talk on Optical Properties of Black Phosphorous (BP) stood out for me. This was in Session SW1R, the first talk by Xiamou Wang of Yale University. The authors gave some intriguing glimpses into what was a new topic for me. Graphene by now is well known as a 2D material. BP was a new material to me. It seems that it lies somewhere between Graphene and other Two Dimensional Materials (TDMs) such as Molybdenum DiSulphide. BP bridges the optical and electronic gaps.

The optical gap of Graphene is 0, while that of TDMs is large, BP is about 1.3eV for monolayer BP . The electronic gap bridge comes about because Graphene has low on/off ratio  and high electronic mobility, while TDMs have high on/off ratio and low mobility. BP has a medium on/off ratio and medium mobility.

Certainly of the 70 odd 2D materials available BP seems to be the new exciting thing! So it gives me something new to learn!

Some papers mentioned in the talk that you may want to look at:

PNAS, 112, 4253, 2015

Nano Letters, 14, 6414, 2014

Nature Photonics, 9, 247, 2015

Then there was the special symposium to mark 20 years of Photonic Crystal Fibers. In the symposium I really enjoyed the talk by Arnaud Mussot (SW1I.3) on topographic fibers. The central idea here is that the outer diameter (and through that the modal properties such as dispersion, non-linearity etc.) of the fiber can be varied along the length of the fiber. This variation can be sinusoidal or in some cases follow other profiles too. The applications discussed were on modulation instability, solitons. Though ofcourse there are many others. Some papers mentioned in the talk that you may want to look at:

Optics Letters, 37, 4832, 2012;

Physical Review A, 87, 013813, 2013;

Optics Express 23, 3869, 2015;

Optics Letters 40, 455, 2015;

Physical Review Letters, 116, 143901, 2016.

But that wasn’t all!

The event on Climbing the Ladder brought together 4 panellists who spoke of their career journeys. This was followed by lunch in which people sat in “mentor” or “mentee” chairs and talked to establish a mentor-mentee relationship.

So many of us feel we need some career advice (how to get a post-doc, how to change jobs, where to move to etc.) but we dont know whom to ask or how to find a good mentor. this was an opportunity to meet some excellent mentors and ask these questions, and perhaps start a longer relationship.

For mentors this was an opportunity to give back to the  community by supporting the next generation of professionals and leaders. Helping them navigate the choppy waters of education, careers and the intersection with personal life.

All in all it has been a superbusy and extremely rewarding time at CLEO, meeting people and networking, learning new things.

I hope I will see you there too in the future!

PhD opportunities

City University London will be offering  some PhD positions with funding for exceptional students (see below). If there is an interest in applying to do PhD with me, please get in touch to discuss.

What is Offered

A doctoral studentship will provide:

  • An annual bursary (£16,000 in 2016/17)
  • The full tuition fee for UK and EU students. This award is for 3 years subject to ongoing excellent performance by the student. Applications are welcome from overseas applicants but the applicant must make appropriate arrangements to cover the difference between the overseas and UK tuition fee.

 Eligibility

The studentships will be awarded on the basis of outstanding academic achievement and the potential to produce cutting edge-research.

  • Applicants must hold at least a 2.1 honours degree or merit level Masters degree in a relevant subject (or international equivalent)
  • Applicants whose first language is not English must have achieved at least 6.5 in IELTS or a recognised equivalent
  • Applicants must not be currently registered as a doctoral student at City University London or any other academic institution.

 How to Apply

Applications must consist of: a research degree application form , 3 page research proposal (the proposal must clearly identify the first (Category A) and second supervisor (Category A or B)), proof of academic qualifications, applicants CV, proof of English language proficiency (if the applicant’s first language is not English) and two confidential references (one of which must be an academic reference).

The above documents should be compiled into a single document and submitted to pgr.smcse.enquire@city.ac.uk (Naina and Nathalie) by the 26th May 2016.

Selection Panel

A panel will be put in place to select the students immediately after May 26th. The panel will comprise the Dean, Associate Dean Research and a selection of staff (TBC) from across the School.

By artiagrawal Posted in General

Some more non-linearity

In recent times I have focused my blogposts on events that I attended.

Today I feel some pleasure in going back to writing a bit about my research.

In a recent journal article that we published we explored how an ultra broadband Supercontinuum in the mid Infra Red part of spectrum can be efficiently generated in spiral chalcogenide PCF.

We showed by numerical simulations an SCG spectra that spanned more than 3 Octave from 1.3-11 micron and beyond. The difficulties in generating SCG in these wavelength regimes include lack of sources at appropriate pump wavelengths, such sources of sufficiently high power, as well as waveguides that have zero and flat dispersion near the pump.

With the Equiangular Spiral PCF,  it is possible to modify both the dispersion (making it flat and close to zero @ the choice of pump wavelength)  as well as have a well confined modal field with large non-linearity.

What this work offers along with Disperison and nonlinearity control is the additional control of absorption: possibility  of a cladding  made of the same material as the core (only airholes are introduced for guidance) which overcomes the problem of absorption seen in other proposed/fabricated planar waveguide and step index chalcogenide based designs.

It goes without saying that the results were exhilarating and I now look forward to taking this work further, preferably with someone who can fabricate and test the design!

So if you want to collaborate do get in touch!

Optics and exhibitions

Recently I visited two exhibitions and both have completely blown my mind.

The first was the Cosmonauts exhibition at the science museum in London  and the second was the Phillips collection where I  had the opportunity to see the Paul Allen

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Poster from the Cosmonauts exhibition

collection in  Washington DC.

So about Cosmonauts first:  the exhibition tells the story of Soviet Russia’s foray into space and how it put the first man-made objects, landed them on other planets and launch the first man into space.  Imagine seeing the space suit worn by Valentina Tereshkova the first woman in space!  It was a stunning experience as well as a very moving one.

There was a letter there from a young girl who asked the soviet space agency to send her to the moon because she had the appropriate fur coat and boots!  She said that she was willing to die but would they please please send her!

This passion for space and exploration is not new and the exhibition showed the excitement generated the world over when  when the Gagarin went into space.

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Poster from the Cosmonauts exhibition

What does this have to do with optics?

Well if you’ve seen the new photographs from Pluto they completely break apart the theories that we have about planets.  How can a planet that is not in geologically active have mountains?

The roll that optics has to play in all this is  is opening our eyes to new wavelengths-  enabling us to observe the world in frequencies that we haven’t been able to do so before  as effectively as we can now.  With the new sources and detectors in the IR and far IR we should be able to detect signs of life potentially!

So with optics to the stars then!  And this time we can possibly travel there too.

And now about the Paul Allen collection: at the OSA  winter leadership meeting there was a reception held at the Phillips collection,  and I’ll gallery in D.C.  The Paul Allen collection on landscape painting with charted how landscape painting has changed over 400 hundred years was being shown.

The sumptuous  collection of Monets, Manets, Signacs, even a Matisse and Kandinsky, a surreal Magritte were simply fabulous! Unfortunately i could not take photographs of these and post them here.

Optics took me to DC and it was optics that give me the opportunity to see these masterpieces.  Not to mention that there was the visual optical process of actually looking at these paintings.

Overall I would say optics is a win-win! I had a fabulous time and I hope you can  experience what Art other sciences bring in conjunction with optics in to our lives.

 

Opportunities for research in London

There are some exciting opportunities for undergraduate , postgraduate and post-doctoral level work (research) to come to London. Monthly stipend and return airfare is included!

Partners from Delhi, Bangladesh, Shanghai and more read on…

Students from partner universities can apply for these UG/PG/PostDoc/Staff levels

  1. http://www.emleaders.eu/index.asp?p=2208&a=2208: Deadline 23 December
  2. http://www.em-intact.eu/index.asp?p=2066&a=2066: Deadline 3 January

I would be happy to act as host and agree a research programme. Get in touch!

Partner institutions for 1 are:

United International University – JOINT COORDINATOR
Bangladesh
Website
Info sheet
Academic offer
 
Bangladesh University of Engineering and Technology
Bangladesh
Website
Info sheet
Academic offer
 
Khulna University of Engineering and Technology
Bangladesh
Website
Info sheet
Academic offer
 
National University of Science and Technology
Pakistan
Website
Info sheet
Academic offer
 
Mehran University of Engineering and Technology
Pakistan
Website
Info sheet
Academic offer
 
Kathmandu University
Nepal
Website
Info sheet
Academic offer
 
Royal University of Bhutan
Bhutan
Website
Info sheet
Academic offer
 
Information and Communication Technology Institute
Afghanistan
Website
Info sheet
Academic offer
 
Shanghai Jiao Tong University
China
Website
Info sheet
Academic offer
 
University of Calcutta
India
Website
Info sheet
Academic offer
 
Bangkok University
Thailand
Website
Info sheet
Academic offer
 
Multimedia University
Malaysia
Website
Info sheet
Academic offer
 
Universitas Pelita Harapan
Indonesia
Website
Info sheet
Academic offer

Partner institutions for 2 are:

Asian Partners

United International University United International University Fact Sheet
Bangladesh University of Engineering and Technology Bangladesh University of Engineering and Technology Fact Sheet
BRAC University BRAC University Fact Sheet
National University of Science and Technology National University of Science and Technology Fact Sheet
Mehran University of Engineering and Technology Mehran University of Engineering and Technology Fact Sheet
Kathmandu University Kathmandu University Fact Sheet
Royal University of Bhutan Royal University
of Bhutan
Fact Sheet
Kabul University Kabul University Fact Sheet
University of Delhi University of Delhi Fact Sheet
Southeast University Southeast University Fact Sheet
University of Malaya University of Malaya Fact Sheet
Bangkok University Bangkok University Fact Sheet
Institut Teknologi Bandung Institut Teknologi
Bandung
Fact Sheet

Fun, Games and Teaching

Recently in my first year Physics class I posed a problem to my students:

What is the most efficient way of determining if a given point lies inside a given polygon?

At the end of the context, I give the code my students sent me. And a game one of them created!!!

This is a real and living research problem. For me the context  is this: in the Finite Element mesh I construct, sometimes we want to move one of the nodes in a mesh element so that the photonic structure/boundary is better represented. The trouble is determining which node to move out of all the nodes in the element. Since you may have to do this for a large mesh with close to 100,000 elements, it must be fast, accurate and reliable.

So the students sent me this:

  1. Python code (by Riad Ibadulla) :

n=int(input(“Enter the size of polygon: “))
#input——————————————
x=[]
y=[]
z=0
j=0
print(“Enter the coordinates of polygon: “)
for i in range(n):
x.append(int(input(“x=”)))
y.append(int(input(“y=”)))
print(“Enter the coordiantes of the point: “)
x0=input(“x=”)
y0=input(“y=”)
#checking————————————–
for i in range(n):
z=(x0-x[i])*(y[i-(n-1)]-y[i])-(y0-y[i])*(x[i-(n-1)]-x[i])
if z>0:
j+=1
if j==n:
print(“belongs to polygon”)
else:
print(“out of the polygon”)

2. A game, Galactic Waste Man (by Kenneth Evbuomwan) that uses logic that is central to the problem posed. The code is available here: GameController.

So can your algorithm match/beat what my first years have done?

 

A different kind of pride

Usually my blogposts here are about topics thaWP_20151029_18_17_34_Prot interest me (on Science, policy, equality and diversity etc.) and my own research.

Today I feel especially proud writing about my PhD student, Swetha. Swetha entered the UK ICT Pioneers competition of the EPSRC  in the information overload category. She  made a short film about her research work, which took her to the finals of the competition and was amongst only 15 chosen, with only 4 including her in her category. There she presented her work on a poster and explained it to a rather tough panel of judges drawn from EPSRC, companies like Hewlett Packard, Samsung and Facebook.

As a student only in her first year of PhD she was the youngest (in research age and stage of PhD). So this was a huge achievement. It has also spurred her onto believe in her own merit and that she can do great Science.

It was a lovely experience for me as a supervisor to attend the awards night and see my student feted and acknowledged.

Academia is a strange life: for a very long time we work hard to reach the lowest rung of this ladder (10+ years of study to finish postdoc and get a first faculty position in many cases). We are regarded  as junior for so long that it is often not till much later when we supervise PhD students that the realization of the end of our student days dawns upon us.

Having one’s own students do well is the best possible way to realize I am no longer a student!! So my thanks to Swetha.

 

Nature’s paint palette

I wrote some time ago about structural colour.

More now on that theme.

Some creatures, such as butterflies of the Papilio genus, have sculpted multilayers on their scales: that is they have 2d shapes (for example,like golf balls or dimples) in arrays that maybe interlinked.

Light reflecting off the bottom of the depression (which acts as a 1D structure) is of a different wavelength (and hence colour, say yellow) to that reflecting off the walls (also acting as a 1d structure), say blue. At a far distance the two colours, yellow and blue seem to mix and give the impression that the wings are green!

Another very neat example of structural colour!