Terahertz quantum cascade lasers with &gt;1 W output powers

Lianhe Li,E.H Linfield,Jingxuan Zhu,Li Chen,A.G Davies,A Valavanis,P Dean,J Freeman

doi:10.1049/el.2013.4035

Abstract

Terahertz (THz) frequency quantum cascade lasers emitting peak powers of >1 W from a single facet in the pulsed mode are demonstrated. The active region is based on a bound-to-continuum transition with a one-well injector, and is embedded into a surface-plasmon waveguide. The lasers emit at a frequency of ∼3.4 THz and have a maximum operating temperature of 123 K. The maximum measured emitted powers are ∼1.01 W at 10 K and ∼420 mW at 77 K, with no correction made to allow for the optical collection efficiency of the apparatus.

Highlights

Terahertz (THz) frequency radiation has many potential applications, ranging from imaging and chemical sensing through to telecommunications [1, 2]
The radiation was collected from a single facet and the power was measured using an absolute terahertz power meter (Thomas Keating), which was butted against the cryostat window
The effective mirror losses from the device facets, which scale inversely with the cavity length, are likely to be responsible for this difference

Summary

Introduction

Terahertz (THz) frequency radiation has many potential applications, ranging from imaging and chemical sensing through to telecommunications [1, 2]. The radiation was collected from a single facet and the power was measured using an absolute terahertz power meter (Thomas Keating), which was butted against the cryostat window. Unlike earlier reports of high-power THz QCLs [10, 11], neither a lightpipe nor a Winston core was used here despite a separation of ∼3.5 cm between the power meter and the device facet. Results: Fig. 1 shows the dependencies of the measured Ppeak on both the ridge width and the cavity length for the as-cleaved devices at a heatsink temperature of 10 K.

Results

Conclusion