High-efficiency second harmonic generation of blue light on thin-film lithium niobate

Abstract

The strength of interactions between photons in a χ(2) nonlinear optical waveguide increases at shorter wavelengths. These larger interactions enable coherent spectral translation and light generation at a lower power, over a broader bandwidth, and in a smaller device: all of which open the door to new technologies spanning fields from classical to quantum optics. Stronger interactions may also grant access to new regimes of quantum optics to be explored at the few-photon level. One promising platform that could enable these advances is thin-film lithium niobate (TFLN), due to its broad optical transparency window and possibility for quasi-phase matching and dispersion engineering. In this Letter, we demonstrate second harmonic generation of blue light on an integrated thin-film lithium niobate waveguide and observe a conversion efficiency of η0 = 33, 000%/W-cm2, significantly exceeding previous demonstrations.

Electro- and Thermo-Optics Response of X-Cut Thin Film LiNbO3 Waveguides

“…Lithium niobate, by virtue of its EO properties, has been widely used for decades to implement high-speed optical modulators [15]. Recently, with the development of ultra-low loss optical circuits in thin film lithium niobate (TFLN) [16], such capabilities have been leveraged also in nanophotonic PIC formats [17][18][19][20] and in the last few years, this new photonic platform has enabled a series of ground-breaking results also in nonlinear [21] and quantum optics [22,23,24].…”

Efficient Photonic Integration of Diamond Color Centers and Thin-Film Lithium Niobate

“…To overcome these challenges, heterogeneous integration with mature nanophotonic material platforms is a promising approach. − Thin-film lithium niobate (TFLN) offers many advantages over alternative photonic materials via large χ (2) nonlinearity. This enables many applications, including strong electro-optic modulation and frequency conversion, − piezoelectric transduction, , and periodic poling for quasi-phase matching and nonlinear frequency conversion. , …”

“…This enables many applications, including strong electro-optic modulation and frequency conversion, 27−30 piezoelectric transduction, 31,32 and periodic poling for quasi-phase matching and nonlinear frequency conversion. 33,34 Here, we demonstrate efficient heterogeneous integration of a diamond nanobeam featuring incorporated SiV color centers with a TFLN platform using a mechanical pick-and-place approach. 15,35−37 By precisely placing double-tapered diamond nanobeams, we demonstrate the bridging of a gapped TFLN waveguide with a diamond-to-LN transmission efficiency of 92 ± 11% per facet at 737 nm, corresponding to the SiV ZPL wavelength, averaged across multiple measurements.…”

Wavelength-Sensitive Superconducting Single-Photon Detectors on Thin Film Lithium Niobate Waveguides

“…Lithium niobate has been for decades the material of choice for integrated photonics, not only because of its electro-optical properties: its noncentrosymmetric structure makes it suited also for three-wave mixing processes, needed for efficient on-chip nonlinear optics. Since ultralow-loss PICs have been demonstrated in thin film lithium niobate (TFLN), the interesting properties of this material have been leveraged also in nanophotonic circuits, demonstrating disruptive results in quantum photonics, nonlinear optics, and ultrafast modulation of light on a chip . In recent years, on-chip detection has also been proven on TFLN optical circuits, taking advantage both of silicon detectors and superconducting nanowire single-photon detectors (SNSPDs). ,, SNSPDs offer very competitive performance in terms of footprint, efficiency, time resolution, and noise when compared to single-photon detectors based on other technologies .…”