Charge detection using nano-resonators

The separation of leaves in gold leaf electroscopes indicates the amount of charge on them. Detectors that can accurately measure small fluctuations in charges are extremely important in a lot of applications including quantum sensingMost of these sensitive detectors such as the ones based on Josephson junctions and single-electron transistors operate at temperatures below 1 K. These detectors rely on rapid change in the output in response to minute charge fluctuations at the input. Nonlinear systems at bifurcation points do exhibit such abrupt changes in output for small changes in the input. Such bifurcation amplifiers have previously been demonstrated using Josephson junction and mechanical resonators. Previous demonstrations using mechanical resonators were able detect charge fluctuations on the order of 100 electrons at room temperature. In our work, we have taken advantage of the exquisite force sensitivity of 2D material nano-electromechanical resonators in conjunction with a bifurcation amplifier implementation to sense charges on the order of 10 electrons in real-time at room temperature. We have also implemented a set-reset flip-flop using the same device to record short-lived charge fluctuations until an erase/reset operation is performed.  



The paper is published in APL.

More details can be found here

Congratulations Aneesh, Nishta and Swapnil!

Ph.D. Admissions


Here is some information that might be useful to prospective students.

What programs at IISc are appropriate for me?

Students generally pick departments that are closest to their undergradaute major. While this is probably ok, you might miss out on some really exciting research going on in other departments. e.g. While ECE and DESE might seem like a very good choice for students from ECE  background, they might want to explore departments such as Physics and CeNSE. There is a lot of device physics that happens in these departments that might be of interest to you. So make a list of broad areas that you are interested in and then look up the websites of the departments.

What are the modes of entry in IISc? Continue reading “Ph.D. Admissions”

Parmeshwar receives DCMP Graduate Student Travel Award!


Parmeshwar Prasad is selected for DCMP Graduate Student Travel Award APS 2019 March APS Meeting in Boston.

The DCMP Graduate Student Travel Awards were established to assist the professional development and careers of graduate student researchers and are presented through the APS Division of Condensed Matter Physics (DCMP).


Aneesh’s paper in Optics letter is Editor’s pick!

Aneesh’s recent work in Optics Letter has been highlighted as Editor’s pick.

Article presented an on-chip optical transduction scheme to detect the strain and displacement of graphene based nanoeletromechanical system. The scheme, if implemented using ring loaded Mach-Zehnder interferometer with modest optical quality factors of about 2500, should be able to achieve displacement sensitivity of about 30fm/rtHz  and strain sensitivity of 6×10^-6 % .

He is currently working on implementing the scheme.

See the paper here