Athermalization of the Lasing Wavelength in Vertical‐Cavity Surface‐Emitting Lasers

Abstract

A concept for vertical‐cavity surface‐emitting lasers (VCSELs) is proposed and demonstrated to obtain a lasing wavelength with unprecedented temperature stability. The concept is based on incorporating a dielectric material with a negative thermo‐optic coefficient, dn/dT, in the distributed Bragg reflectors (DBRs) to compensate the positive dn/dT of the semiconductor cavity. In a short cavity, the optical field has a significant overlap with the DBRs, and the redshift of the lasing wavelength caused by the semiconductor cavity can be compensated by the negative dn/dT of the DBRs. Here, proof of this concept is presented for optically‐pumped VCSELs emitting at 310 nm, demonstrating a lasing wavelength that even blueshifts by less than 0.1 nm over an 80 °C range with a maximum slope of –3.4 pm K−1. This is to be compared with a redshift of 1–1.5 nm over the same temperature range reported for III‐nitride blue‐emitting VCSELs. Furthermore, this method can also be implemented in VCSELs with longer cavity lengths by including a dielectric layer between the semiconductor and the DBR. The approach used here to obtain a temperature‐stable lasing wavelength is generic and can therefore be applied to VCSELs in all material systems and lasing wavelengths.

High Q-Factor and Low Threshold Electrically Pumped Single-Mode Microlaser Based on a Single-Microwire Double-Heterojunction Device

“…The speculation was further tested. PL measurements depending on the pumping fluence were conducted using a testing system via a 266 nm fs pulsed laser. , The schematic view of the measurement equipment and optical path is shown in Figure S4. A hexagon-shaped ZnO:Ga MW with a diameter of about 20 μm was pumped optically.…”

“…With the advancement of optoelectronic device miniaturization and various advantages, such as low energy consumption, advanced design, compact structure, and high reliability, individual lasing sources must be scaled down and integrated into small areas or volumes to a microscale or even a nanoscale. ,− The construction of laser devices, typically carried out through high cost, high-temperature vacuum processing, and rigid substrates, has become increasingly complex, time-consuming, and expensive. ,− In essence, achieving high-performance micro- and nanolasers upon electrical pumping remains challenging, primarily due to several drawbacks: (i) Significant nonradiative loss occurs at high carrier density levels necessary for population inversion; , (ii) small cavities inherently possess high electrical resistance; , (iii) resistant heat loss is generated within metal/semiconductor and p–n junction region; (iv) lasing suppression can be induced by conductive functional layers in electroluminescence (EL) devices; and (v) substantial losses occur around the resonant cavity due to high-level current injection and other factors. , These perspectives pose substantial obstacles to further advancement of realistic microlaser devices. Therefore, it is imperative to propose rational laser structures.…”