Placement Information
Year you started your placement
2015
Placement period
May – August, September – December
Supervisor’s name
Vahid Sandoghdar
Project Details
Overview
The Sandoghdar Division at the MPL is a dynamic group that focuses upon investigating the light-matter interaction at the nanometer scale by using a combination of techniques from quantum optics, laser spectroscopy, cryogenics, and nanofluidics. There are four main areas of research, namely nano-quantum-optics, plasmonics, optical nanoscopy and biophotonics. Research projects in the group ranges from investigation of optical processes at the single-photon and single emitter level of solid-state samples, quantum dots, and organic molecules to high-speed tracking of nanoparticles tagged to proteins or single cells to monitor specific cellular processes of interest such as movement through synthetic lipid membranes.
Project objectives
My project was to characterize the photophysical properties of NV-center nanocrystals and to quantify their quantum efficiency.
Single photon sources have been of great interest in quantum optics due to its vast number of applications, in particular in quantum information processing and quantum teleportation. Nitrogen-vacancy centers in diamond nanocrystals are one type of single photon source that holds promise due to their stability at room temperature. They are considered to be single two-level quantum systems. Since excitation and subsequent decay to the initial ground state requires a finite time, only one photon is emitted at a time.
The experimental setup includes either a 532nm pump or pulsed laser, which is focused onto a nanocrystal in air, oil, and water. Fluorescence light collected with a confocal microscope from a single NV center was analyzed either by a spectrometer or a Hanbury-Brown-Twiss configuation where the emitted photons are subsequently detected by silicon avalanche photodiodes (APD). The spectra of a single NV center contains characteristic zero phonon lines (ZPL) at 575nm and/or 637nm. The photons collected on the APDs were used to measure the second-order correlation function, which would demonstrate the non-classical properties of the light and that the single NV center is indeed a single photon emitter. Lifetime measurements were performed to measure the decay rate, and hence, the emission rate, of the two-level system. With changing refractive indices, the lifetime theoretically changes by a factor of 1/n, n being the refractive index. Back-focal-plane imaging was used to measure the dipole orientations of single NV centers. The precise size of these nanocrystals were determined using atomic force microscopy. Combined with computational simulations performed in Matlab, the experimental data collected from all afore-mentioned measurements would allow the precise quantification of the quantum efficiency of single NV centers in diamond nanocrystals.
Research outcomes
Project status
Completed
Expected completion date
12/15/2015
My Co-op Experience at MPI
Why did you apply for a placement with Max Planck Institute?
I applied specifically to the Max Planck Institute for the Science of Light because I wanted to learn optics and I wanted to do so from the best in the field. Dr. Sandoghdar and his group have expertise in applying sophisticated techniques that allows for high degree of control and finesse in studying light-matter interactions, which currently is being applied to carry out super-resolution imaging and high-speed tracking and manipulation of biological molecules embedded in membranes or secreted from cells. I hope to apply these fundamental experimental and theoretical knowledge to my future research pursuit in studying mammalian systems biology.
What recommendations do you have for students who wish to participate in MPI-UBC exchange program?
Be confident and persistent. Show how much you want this position and what you are passionate about. I obtained this opportunity the second time I applied for it. Grades are not the single most important determining factor. Having prior research experience, I believe, is just as essential, if not more so, than having high academic standing in courses. It would help immensely in adapting quickly and smoothly in a high-pressure environment such as those at Max Planck Institutes, in establishing a productive and positive working relationship with colleagues, as well as getting the most out of the resources and knowledge at your disposal. Being able to work at the MPI is a unique one in that most of the labs are filled with PhD students and postdocs. Don’t be afraid to ask questions. Work hard to develop your skills. I would also suggest, if permitted by your PI, to develop your own project and to consult with your supervisor along the process, as this would give you the opportunity to explore what you really want to do and the questions you want to find answers to.
Tell us about your travels and cultural experiences in Germany and the rest of the Europe
Germans love their beer festivals (the one in Erlangen is a ton of fun and has a cozier feel than, say, the much more commercialized Oktoberfest in Munich), sausages and bread. I did have a difficult time at first adapting to the lifestyle here in terms of the food, but because of that I have been pushing myself to learn how to cook healthy nutritious meals, and to put more emphasis on experiencing other parts of the German culture. Germans are very honest and sincere. They say what is on their mind with no filter. I find that extremely refreshing. Their irony and jokes are also quite subtle; most are insinuated. The lab consists of people from all different backgrounds, such as Spain, Greece, Britain and China, so I have been exposed to a diverse range of cultures which has definitely been an eye-opening experience. Strangely and perhaps ironically, living abroad and meeting people from other cultures have made me really think about my own personal identity.
I have been traveling extensively during my time here in Europe. In Germany, I have been to Berlin, Wurzburg, Bamberg, Nuremberg, and make frequent trips to Munich. Bamberg is a very cute and adorable Medival town, one of the few that was not damaged by the war, so it’s definitely worth visiting. Berlin is a must. I visited many of the (free) exhibitions and museums pertaining to World War II and the Holocaust. There is a rich mix of history and modernity in the city.
As Germany is centrally-located, I have been able to visit many other countries in Europe, including the UK, Sweden, Denmark, Austria, the Czech Republic, and France. There are many parallels amongst all the cities, such as there being a castle on a hill, a cathedral/church in the heart of the city, and a bridge over a river etc. However, each place still has their own little perks and has something different to offer. Nice was absolutely beautiful, filled with beautiful beaches, fun rave parties along the ocean, and lots of smoothies and margaritas. I have to say I really enjoyed Sweden and Denmark. I visited Copenhagen (Denmark) and a friend of mine and I drove to the countryside, to a little town called Kivik, just outside Lund, where there were nevery-ending stretches of white sandy beaches and green forests. It was also apple harvest season there so we tasted some amazing Swedish apples and saw a huge painting made with apples. In Copenhagen, there is a pretty hippie district called Christiania, where apparently “no laws apply,” so you can imagine what people sold and did there. I definitely recommend people to visit that part of the city since it’s very different from the rest of Copenhagen, and has a lot of funk and character.
