ELOS 2022

Sanjeeb Dey

Sanjeeb Dey, Speaker at Optics Conferences
Ramakrishna Mission Vidyamandira, India
Title : A theoretical study on anti-laser with EM perspective


Our study on tunable anti-lasing or commonly known as coherent perfect absorption can be expressed with a simple formula as  for TE-polarization. The expression can be used to estimate all necessary parameters required for anti-lasing, such as, materials type, it's thickness, angle of incidences and wavelength of the light.

Recently, it has been observed that a tremendous interest is found in the anomaly of anti-lasing, particularly in micro or nano-structures, where the incident lights shining from the opposite side of anti-lasing materials are 100% absorbed. The positive imaginary part of a complex permittivity is the essential requirement for absorbing media, which is involved in the occurrence of anti-lasing. Apart from these the dependence of anti-lasing varies with 1: the concentration or density of the medium 2: the wavelength of shining lights, and 3: the angle of incidence of the lights. This theoretical expression can describe all the parameters of anti-lasing. This presentation contains how one can derive the expression from EM waves for oblique incidences with the help of Maxwell's and EM boundary conditions. We will see several examples of anti-lasing with the help of the expression.


  1. Chong Y. D., Ge L., Cao H. and Stone A. D. “Coherent perfect absorption: time-reversed laser”, Phys. Rev. Lett. 105 053901(2010).
  2. Gmachl C. F., “Suckers for light”, Nature 467 37-9 (2010).
  3. Wan W., Chong Y. D., Ge L., Noh H., Stone A. D. and Cao H., “Time reversed lasing and interferometric control of absorption”, Science 331 889-92 (2011).
  4. Dey S., and Singh S., “An electromagnetic perspective of coherent perfect absorption”, Phys. Scr. 94 015502 (7pp) (2019).
  5. Dey S., “Coherent perfect absorption using Gaussian beans”, Opt. Comm. 356 515-21 (2015)
  6. Dey S. Singh S. and Rao D. N., “High precision position sensor based on CPA in a composite multi-layered system”, Opt. Exp 26 8 (2018).
  7. Johnson P. B. and Christy R. W. “Optical constants of noble metals”, Phys. Rev. B 6 4370-9 (1972).

What will audience learn from your presentation?

  • The logical step-by-step argument for the development of the theoretical formula of anti-lasing.
  • Comparison of some real-time examples of anti-lasing with the expression.
  • The usefulness of the formula to achieve anti-lasing.
  • Improvement of accuracy in our anti-lasing experiments.
  • The future aspect of the formula



Dr. Sanjeeb Dey is working as an assistant professor at Ramakrishna Mission Vidyamandira in Computer Science and Electronics Department. He graduated from Banaras Hindu University (BHU) and got a doctoral degree (Ph. D.) from the University of Hyderabad (UOH) in 2017. He just set up his lab to work on quantum optics in the vicinity of theoretical research, which is actively involved in light-matter interaction, plasmonics in the waveguide, nonlinear optics, meta-materials, etc. in the single or stratified medium.