Courses taught at IISER Mohali

Elective Courses:

Main Courses:

Best Teacher Award 2016

Winner of the best teacher award of the year 2016 for the excellent contribution to teaching at IISER Mohali. 

 In Picture: Prof. N. Sathyamurthy (Former founding Director, Left), Prof. N.G. Prasad (Former Dean, Right).

 Physics Education:

Because of my interest in physics education, I have developed new experiments for physics teaching. In addition to the main research activities, I have contributed willingly to the teaching program and teaching activities during my initial years at IISER Mohali.  Two experiments from this work on physics education are published. In addition, I have delivered public lectures at various places on educational events to motivate students for science and research.

Cover page highlight in the American Journal of Physics

An experiment on quantum diffraction of a laser beam by a mechanical chopper was published in American Journal of Physics. This work was highlighted on the cover page of the journal. 

A mechanical chopper is a general purpose instrument which is used to produce pulses of a light beam in the time domain by obstructing the path of the beam with sharp edge blades. A careful investigation shows that the edges of  the generated laser pulses are not smooth because of diffraction of beam from the sharp edges of the blades of the mechanical chopper. This experiment explains the details of this effect, and it is also used to measure wavelengths of unknown lasers. 






A diffraction pattern of a straight sharp edge appears at the rising and trailing edges of each chopped pulse (time domain capture).

Paper: Diffraction effects in mechanical chopped laser pulses. Samridhi Gambhir and Mandip Singh. Am. J. Phys. 86 (6), Jun 2018. PDF


Frequency comb generation and other nonlinear effects by using nonlinearity of a PN-Junction diode

An ideal ohimic resistance is linear, where a voltage drop across it is proportional to current passing through it.  If two different sinusoidal voltage signals are applied across an ideal resistance, then two different but independent current signals are developed across the resistor, which are proportional to their respective voltage signals. Thus, current signals are not coupled to each other, as they can be controlled independent to each other by changing corresponding voltage signals. However, if resistance is a function of voltage applied across it, then the generated current signals of different voltage signals can mix with each other. New frequency harmonics are produced as a result of nonlinearity.

In this experiment, a general purpose PN junction diode is used as a nonlinear element since the V-I characteristics of a PN junction diode are nonlinear. Operational amplifiers are used in this experiment to add voltage signals and to extract current signals. Sum and difference frequency generation is studied along with a frequency comb generation up to the 20th harmonics of the driving voltage signal. 




Diode equation-2 expansion looks like polarization dependence on the electric field of a nonlinear medium.

Paper: Intrinsic nonlinearity of a PN-junction diode and higher order harmonic generation. Samridhi Gambhir, Arvind and Mandip Singh. IAPT Physics Education. Vol 32, No.2. Apr-Jun 2018. PDF