Optically pumped nanowire lasers: invited review

Abstract

This paper reviews several topics related to optically pumped ZnO nanowire lasers. A systematic study of the various properties of a device as it evolves from the regime of amplified spontaneous emission to laser oscillation above threshold is presented. The key dependence of the laser threshold on nanowire diameter is demonstrated and explained by means of a thorough study of guided modes in semiconducting nanowires for a nanowire-on-substrate geometry. A 'head on' detection geometry is used to measure the far-field profile of a nanowire laser and thus identify the modes responsible for lasing. Finally, the temperature behavior of a nanowire laser is reported, and possible mechanisms that may be responsible for gain are suggested.

Lasing from individual GaAs-AlGaAs core-shell nanowires up to room temperature

“…2a is the periodic modulation of the spontaneous emission intensity reflecting regularly spaced longitudinal FP modes separated by 10 ± 1 meV. The spacing of these modes is expected to be dE ¼ (:pc)/(n group Á L), where n group ¼ n eff À l (d neff /dl) is the group index of the axial guided mode 19 with an effective mode index n eff and L is the NW length (see Methods section). We measured L for all the NW lasers using optical microscopy and calculated the group indices n group ¼ 4.85 and 4.86 for the transverse electric (TE) 01 -and transverse magnetic (TM) 01 -guided modes, respectively.…”

“…Furthermore, first indications of amplified spontaneous emission and lasing have been reported from optically pumped GaSb 16 and GaAsGaAsP core-shell NWs 17 . For NW lasers that use GaAs as a gain medium, theoretical analyses of the modal gain 13,18,19 have indicated that continuous wave lasing should be possible in detached NWs. The end-facet reflectivity (B0.6) is sufficient to reach transparency in NWs with a length of a few micrometres by engineering the confinement of the optical mode via their diameter 7,13 .…”

Transfer printing of semiconductor nanowire lasers

“…Semiconductor NWs are expected to be a key component across numerous applications, and one of the most investigated is their use as nanoscale laser sources (see [1][2][3][4][ [22][23][24][25][26][27][28][29] and references therein). Since the report of the first NW lasers over 15 years ago [4], research progress has been phenomenal, and NW lasers built from different materials, e.g.…”

“…Since the report of the first NW lasers over 15 years ago [4], research progress has been phenomenal, and NW lasers built from different materials, e.g. Group III-nitrides [22][23][24], Group II-VI [25], Group III-V [26][27][28], perovskites [29][30][31], and with operating wavelengths extending from the ultraviolet to the infrared have been demonstrated. The properties of NW lasers such as their highly localised emission and extremely reduced foot-print ensure that they will be key coherent light sources for nanophotonics-enabling technologies, e.g.…”

High refractive index in wurtzite GaP measured from Fabry-Pérot resonances

“…In Fig. 3, the bulk refractive indices of WZ GaP are plotted considering either the HE 11 or the TE 01 as the excited mode. If we would assume the TE 01 to be the excited mode, the bulk refractive index would decrease with energy below the band gap, which would be unprecedented for bulk materials.…”