Broadband continuous single-mode tuning of a short-cavity quantum-cascade VECSEL

Journal Article · 23 September 2019 · Nature Photonics

DOI: https://doi.org/10.1038/s41566-019-0518-z · OSTI ID:1575261

Curwen, Christopher A. ^[1]; Reno, John L. ^[2]; Williams, Benjamin S.  ^[1]

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1. Univ. of California, Los Angeles, CA (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Changing the length of a laser cavity is a simple method for continuously tuning the wavelength of a laser but is rarely used for broad fractional tuning, with a notable exception of the vertical-cavity surface-emitting laser (VCSEL). This is because, to avoid mode hopping, the cavity must be kept optically short to ensure a large free spectral range compared to the gain bandwidth of the amplifying material. Terahertz quantum-cascade lasers are ideal candidates for such a short cavity scheme as they demonstrate exceptional gain bandwidths (up to octave spanning) and can be integrated with broadband amplifying metasurfaces. Our report presents such a quantum-cascade metasurface-based vertical-external-cavity surface-emitting laser (VECSEL) that exhibits over 20% continuous fractional tuning of a single laser mode. Such tuning is possible because the metasurface has subwavelength thickness, which allows lasing on low-order Fabry–Pérot cavity modes. Good beam quality and high output power are simultaneously obtained.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
• Grant/Contract Number: AC04-94AL85000; NA-0003525
• OSTI ID: 1575261
• Report Number(s): SAND-2019-4109J; 674633
• Journal Information: Nature Photonics, Vol. 13, Issue 12; ISSN 1749-4885
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English