Nonlinear Infrared Photodetection Based on Strong Nondegenerate Two‐Photon Absorption of Perovskite Single Crystal

Abstract

Halide perovskites have been recently shown to exhibit strong nonlinear optical properties such as two‐photon absorption, second harmonic generation, etc. In this work, the nondegenerate two‐photon absorption, i.e., when the energies of two photons absorbed are not the same, of methylammonium lead bromide single crystal is studied. It is found that the nondegenerate two‐photon absorption is much stronger than the degenerate two‐photon absorption. For the photon pair ℏω1 = 2.96 eV, ℏω2 = 0.73 eV, the nondegenerate two‐photon absorption coefficient reaches 51.3 cm GW−1, which is around 6 times that of degenerate two‐photon absorption. Taking advantage of the strong nondegenerate two‐photon absorption, a nonlinear infrared pulse photodetector based on the combination of a methylammonium lead bromide single crystal and a silicon photodiode is developed. The infrared femtosecond laser pulses at 1700 nm can be well measured with a resolution on the order of 1 nJ and responsivity of 68 V W−1. These findings provide novel insight for the understanding of nondegenerate nonlinear optical properties in halide perovskites and may open a new avenue for the development of high‐sensitivity infrared photon detection.

Ultrafast optical limiting based on non-degenerate two-photon absorption in Ga2O3 single crystal

“…The large width and fast decay of PIA signal agree with previous studies on the ND-TPA effect in semiconductors. 11,14,16 While the photon energies of pump (3.5 eV) and probe pulses (1.65~2.76 eV) are smaller than the band gap of β-Ga2O3 (~4.8 eV), the non-degenerate two-photon absorption leads to the sum of photon energies higher than then band gap, resulting in the PIA signal around zero time-delay. The energy diagram for ND-TPA in β-Ga2O3 is illustrated schematically in Fig.…”

“…Recently, non-degenerate TPA (ND-TPA) effect, where two photons with different wavelengths are absorbed, has attracted increasing attention due to its applications in mid-infrared detection, all-optical switching, and quantum optics. [8][9][10][11] It has been reported by several groups that the magnitude of ND-TPA in semiconductors could be significantly enhanced compared with D-TPA, which is highly promising for OL application. [12][13][14][15][16] Therefore, a detailed investigation of ND-TPA phenomenon in semiconductors is highly desirable for future design of ultrafast optical shutters and limiters.…”

“…Previous experiments have reported the degenerate TPA and three-photon absorption effect in β-Ga2O 1 3 single crystals. [8][9][10][11][12][13][14][15][16][17][18][19][20] However, the ND-TPA effect in β-Ga2O3 remains largely unaddressed and the spectrum dispersion of ND-TPA in β-Ga O is still elusive. 21,22 2 3 In this work, we present an ultrafast broadband optical limiter based on ND-TPA effect in β-Ga2O3 (100) single crystal.…”