Prospects and merits of metal-clad semiconductor lasers from nearly UV to far IR

TL;DR

This paper critically evaluates the advantages of metal-clad semiconductor lasers across UV to far IR, finding limited benefits except in far-IR and THz quantum cascade lasers where metal waveguides are already standard.

Contribution

It provides a rigorous theoretical analysis showing that the expected benefits of metal waveguides are minimal for most laser types, clarifying their actual advantages and limitations.

Findings

Limited benefits of metal waveguides for UV to Mid-IR lasers.

Metal waveguides are standard for far-IR and THz quantum cascade lasers.

Waveguiding in these lasers resembles transmission lines more than plasmonics.

Abstract

Using metal-clad (or plasmonic) waveguide structures in semiconductor lasers carries a promise of reduced size, threshold, and power consumption. This promise is put to a rigorous theoretical test, that takes into account increased waveguide loss, Auger recombination, and Purcell enhancement of spontaneous recombination. The conclusion is that purported benefits of metal waveguides are small to nonexistent for all the band-to-band and intersubband lasers operating from UV to Mid-IR range, with a prominent exception of far-IR and THz quantum cascade lasers. For these devices, however, metal waveguides already represent the state of the art, and the guiding mechanism in them has far more in common with a ubiquitous transmission line than with plasmonics.