Giant nonlinear optical activity in two-dimensional palladium diselenide

Abstract

Nonlinear optical effects in layered two-dimensional transition metal chalcogenides have been extensively explored recently because of the promising prospect of the nonlinear optical effects for various optoelectronic applications. However, these materials possess sizable bandgaps ranging from visible to ultraviolet region, so the investigation of narrow-bandgap materials remains deficient. Here, we report our comprehensive study on the nonlinear optical processes in palladium diselenide (PdSe2) that has a near-infrared bandgap. Interestingly, this material exhibits a unique thickness-dependent second harmonic generation feature, which is in contrast to other transition metal chalcogenides. Furthermore, the two-photon absorption coefficients of 1–3 layer PdSe2 (β ~ 4.16 × 105, 2.58 × 105, and 1.51 × 105 cm GW−1) are larger by two and three orders of magnitude than that of the conventional two-dimensional materials, and giant modulation depths (αs ~ 32%, 27%, and 24%) were obtained in 1–3 layer PdSe2. Such unique nonlinear optical characteristics make PdSe2 a potential candidate for technological innovations in nonlinear optoelectronic devices.

Broadband Nonlinear Photoresponse and Ultrafast Carrier Dynamics of 2D PdSe2

“…Indeed, Table S2 in the Supporting Information lists the reported optical modulation parameters of PdSe 2 ‐based lasers, which concluded that PdSe 2 has the excellent and broadband performance in ultrafast lasers. In addition, the modulation depth of our PdSe 2 film at 520 nm is even comparable with that of trilayer PdSe 2 single‐crystal nanosheet, [ 23 ] which implies that the sample via our preparation process possesses the high crystal quality. Particularly, due to the lack of suitable UV saturable absorber, the generation of ultrashort pulses through mode‐locking at UV wavelengths is still lacking; to the best of our knowledge, this is the first time to report the NLO properties of PdSe 2 in the short‐wavelength region, which demonstrates that PdSe 2 is a promising material applied in these short‐wavelength nonlinear devices.…”

“…In particular, PdSe 2 has been proven to perform well in the optical communication field, including the C‐band, near‐infrared (NIR) band, and visible band. [ 21–23 ] Overall, intrinsic and systematic researches, including both NLO response and ultrafast carrier dynamics, are still required as the fundamentals for PdSe 2 ‐based photonic devices.…”

Fast Photothermoelectric Response in CVD‐Grown PdSe2 Photodetectors with In‐Plane Anisotropy

“…Furthermore, the Raman spectra were characterized, and exhibits four notable peaks at ≈143.6, ≈206, ≈221.4, and ≈256 cm −1 , corresponding to the A g 1 , A g 2 , B 1g 2 , and A g 3 modes (Figure 1e), respectively. [ 29 ] As shown in Figure 1f, the peak frequencies are uniform for a given thickness. [ 30 ]…”

Nonlinear Optical Properties and Ultrafast Carrier Dynamics of 2D Indium Selenide Nanosheets

“…In addition, other nonlinear absorption and nonlinear scattering (NLS) responses of these nanomaterials have been used for optical limiting. [21][22][23] As a consequence, deep excavation and a systematic study of their nonlinear optical (NLO) properties are extremely important for the development of high-performance optoelectronic devices based on low-dimensional materials.Indium selenide (InSe) is a III-VI layered material that has become the focus of considerable interest because of its fascinating optoelectronic properties. [24][25][26] Given its high quantumsize confinement effect, InSe possesses a broad adjustable band gap from 1.25 to 2.6 eV when the bulk InSe is reduced to a few layers.…”

“…In addition, other nonlinear absorption and nonlinear scattering (NLS) responses of these nanomaterials have been used for optical limiting. [21][22][23] As a consequence, deep excavation and a systematic study of their nonlinear optical (NLO) properties are extremely important for the development of high-performance optoelectronic devices based on low-dimensional materials.…”