Mid-infrared PbTe vertical external cavity surface emitting laser on Si-substrate with above 1 W output power

Abstract

Mid-infrared vertical external cavity surface emitting lasers (VECSELs) emitting above 1 W output power in pulsed mode and up to 17 mW in continuous mode at −172 °C were realized. Emission wavelength changes from 5 μm at −172 °C to 3.6 μm at 20 °C heat sink temperature. The active medium is a one wavelength thick PbTe layer grown by molecular beam epitaxy on a Si-substrate. It is followed by a 2.5 pair Pb1−yEuyTe/EuTe epitaxial Bragg mirror. The cavity is completed with an external curved Pb1−yEuyTe/BaF2 mirror. The VECSEL is optically pumped with 1.55 μm wavelength laser and In-soldered to Cu heat sink. No microstructural processing is needed.

Continuously tunable singlemode VECSEL at 3.3 µm wavelength for spectroscopy

“…In contrast to our former mirrors realised with BaF 2 /PbEuTe and grown on a curved BaF 2 substrate [6], these Si/SiOmirrors additionally guarantee the necessary transparency for the 1.55 mm pump beam.…”

“…So far, mid-IR VECSELs with wavelength longer than 3 mm have only been realised with IV-VI narrow gap semiconductors (lead salts). Lead salt materials are characterised by their low Auger recombination, high wavelength tunabilty, and tolerance to defects [5,6].…”

Optically pumped VECSELs: review of technology and progress

“…These gain mirrors benefit from utilization of AlAsSb/GaSb DBRs that offer an outstanding index contrast, but they possess poor thermal conductance. At wavelengths beyond 3 µm, VECSELs have been fabricated using PbSe or PbTe active layers grown on BaF 2 [83] or Si [119] substrates; the wavelength coverage of these gain structures extends from 2.65 µm to 6.5 µm [120][121][122]. However, they usually need low operating temperatures for lasing, though lasing at temperatures as high as 52 °C has been demonstrated [123].…”

PbSe quantum well mid-infrared vertical external cavity surface emitting laser on Si-substrates

“…[1][2][3][4] Advantages of VECSELs are their vertical heat flow, easy tunability and very good beam quality, i.e., a very narrow circular output cone. [5][6][7] In contrast, edge emitting lasers emit a strongly astigmatic beam with a large aperture angle in the fast axis.…”