Nanophotonics Research Group

26/07/2025

**New Publication Alert!**

Our latest research has just been published in *Physical Review A*

**"Coupled Two-Dye Gain-Medium-Based Photonic Nanolasers for Short-Pulse Generation"**

We present a novel nanolaser design that integrates **resonantly coupled donor-acceptor dye molecules** to achieve **sub-picosecond pulse generation** with **GHz repetition rates** — all within a **compact photonic cavity**.

Key Innovations:
✅ Two-dye gain medium enabling saturable gain & absorption
✅ Integrated semiclassical FDTD modeling
✅ Pulse-train & frequency-comb emission from miniature lasers
✅ Tunable cavity-mode engineering for ultrafast operation

🚀 Applications: On-chip optical communication, quantum photonics, nanoscale sensing, ultrafast spectroscopy, and more.

🔗 Read the paper: https://doi.org/10.1103/6472-9sky

Nanoscale lasers that generate short pulses at high repetition rates have exciting applications in various fields. However, creating short pulses as well as broad frequency combs in nanoscale lasers is complex and remains a relatively unexplored area. Research has focused on materials with two or mo...

24/06/2025

Our research on “Theoretical Investigation of Slow Gain Recovery of Quantum Cascade Lasers Observed in Pump-Probe Experiments” has just been published in the Optical and Quantum Electronics journal!

In this study, we explore a puzzling phenomenon in quantum cascade lasers (QCLs): why does the laser gain take so long to recover after an intense light pulse when it should theoretically bounce back almost instantly?

🔬 Our findings reveal that hot electrons and cavity dynamics play a more significant role than previously understood. By coupling Maxwell-Bloch equations with thermal transport modeling, we uncover how localized heating within the QCL cavity disrupts gain recovery over tens of picoseconds.

🌡️ When intense pump pulses are applied, the electrons don’t cool down quickly enough, and this delay alters the behavior of QCLs in high-speed or frequency comb applications.

A big thank you to our co-authors, Mrinmoy Kundu, Aroni Ghosh, and Abdullah Jubair Bin Iqbal, for their dedication and hard work!

👉 Read the paper here: https://doi.org/10.1007/s11082-025-08304-y

Time-resolved spectroscopy-based pump-probe experiments performed on quantum cascade lasers (QCLs) exhibit an initial fast gain recovery followed by a slow tail such that the equilibrium gain is not recovered in a cavity round-trip time. This ultra-slow gain recovery or non-recovered gain cannot be....

19/06/2025

This review emphasizes three promising strategies for designing efficient transition metal oxide photoelectrodes for water-splitting applications: (i) element doping, which enhances sunlight absorpti...

13/06/2025

Advanced theoretical investigations are crucial for understanding the structural growth mechanisms, optoelectronic properties, and photocatalytic activity of photoelectrodes for efficient photoelectrochemical water splitting. In this work, we conducted first-principles calculations aimed at designin...

09/04/2025

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29/01/2025

Our newly published Optics Express paper is on the "Today's Top Downloads" list.

28/01/2025

Our article "Toward low-noise on-chip plasmonic three-dimensional biological cell imaging" came out in Optics Express a few hours ago. Enhancing accessibility to affordable and efficient cell imaging tools has been a longstanding worldwide objective for rapid disease detection and diagnosis. In this paper, we present an innovative approach to this goal, introducing a compact, portable, and user-friendly three-dimensional (3D) cell imaging platform leveraging silicon photonics and the surface plasmon coupled emission (SPCE) phenomenon.

Here is the link to the paper: https://doi.org/10.1364/OE.546204