Progress in Photonic-Crystal Surface-Emitting Lasers

Abstract

Photonic-crystal surface-emitting lasers (PCSELs) have attracted considerable attention as a novel semiconductor laser that surpasses traditional semiconductor lasers. In this review article, we review the current progress of PCSELs, including the demonstration of large-area coherent oscillation, the control of beam patterns, the demonstration of beam steering, and the realization of watt-class and high-beam-quality operation. Furthermore, we show very recent progress in the exploration of high brightness of more than 300 MW cm−2 sr−1, obtained with a high output power of about 10 W while maintaining a high beam quality M2 ~ 2. The PCSELs with such high performances are expected to be applied to a variety of fields, such as laser-based material processing, optical sensing (light-detection and ranging (LiDAR)), and lighting, as they retain the benefits of compact and high-efficiency semiconductor lasers.

Recent Progress in Nanolaser Technology

“…For example, Kurosaka et al achieved on-chip beam-steering using photonic crystal band-edge lasers (Figure 3a). [35,36] The emission direction was controlled via the deformation of structural parameters, such as the air-hole shape and the lattice constant. The maximum beam steering angle was ± 30°, and the beam divergence angle was ≈1°.…”

Buried InP/Airhole Photonic‐Crystal Surface‐Emitting Lasers

“…[ 4 ] Both these approaches pose challenges to the epitaxial regrowth process, which needs to be optimized either for complete [ 4 ] or minimal [ 12–15 ] infilling of the etched holes defining the buried PC lattice. While most results on regrown PCSELs so far have been based on the GaAs material system for emission in the near‐infrared wavelength regime around 1 μm, there are a range of important application in the longer wavelength regime (1.2–1.6 μm), e.g., eye‐safe sources for laser imaging detection and ranging (Lidar), [ 16,17 ] free‐space optical communication, [ 18 ] or resonant pumps for erbium lasers, [ 19 ] that can be reached through the InP material system. Recently, McKenzie et al demonstrated the fabrication of 1550 nm PCSELs based on InP infilling of an InGaAsP grating layer, including lasing action from electrical pumping.…”

1.5 μm Epitaxially Regrown Photonic Crystal Surface Emitting Laser Diode

“…Additional applications for such surface emitting InP based devices include free-space communications [19], LiDAR, fibrebased sensing [1], etc.…”

“…PCSEL devices have traditionally been realised with wafer fusion [2]- [5], but more recently epitaxial overgrowth through MBE [1] [20] and MOVPE has been utilised [21]- [24]. This move from wafer fusion to epitaxial regrowth has been critical for achieving high output powers [1] [9]. This is because the wafer fusion interface contains regions of discontinuous crystallinity, that result in undesirable defect states [1].…”

“…This move from wafer fusion to epitaxial regrowth has been critical for achieving high output powers [1] [9]. This is because the wafer fusion interface contains regions of discontinuous crystallinity, that result in undesirable defect states [1]. Epitaxial regrowth allows single-crystal PCSEL structures to be realised with encapsulated voids or fully in-filled photonic crystals [21].…”