A study of random laser modes in disordered photonic crystals

TL;DR

This paper investigates lasing modes in disordered photonic crystals, revealing how disorder influences lasing thresholds, mode localization, and quality factors, and predicting the possibility of ultra-low threshold random lasers.

Contribution

It provides a detailed analysis of lasing thresholds, mode localization, and quality factors in disordered photonic crystals, highlighting the impact of disorder strength and system size on lasing behavior.

Findings

Lasing threshold scales with system size depending on disorder strength.

Minimum lasing threshold occurs at a finite disorder level for large systems.

Super-exponential decrease of lasing threshold with system size at the minimum.

Abstract

We studied lasing modes in a disordered photonic crystal. The scaling of the lasing threshold with the system size depends on the strength of disorder. For sufficiently large size, the minimum of the lasing threshold occurs at some finite value of disorder strength. The highest random cavity quality factor was comparable to that of an intentionally introduced single defect. At the minimum, the lasing threshold showed a super-exponential decrease with the size of the system. We explain it through a migration of the lasing mode frequencies toward the photonic bandgap center, where the localization length takes the minimum value. Random lasers with exponentially low thresholds are predicted.