Up-conversion detection of mid-infrared light carrying orbital angular momentum

Abstract

Frequency up-conversion is an effective method of mid-infrared (MIR) detection by converting the long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate the MIR light carrying orbital angular momentum (OAM) from a difference frequency generation process and perform the up-conversion of it via sum frequency conversion in a bulk quasi-phase-matching crystal. The maximum quantum conversion efficiencies from MIR to visible are 34.0%, 10.4%, and 3.5% for light with topological charges of 0, 1, and 2, respectively, which is achieved by utilizing an optimized strong pump light. We also verify the OAM conservation with a specially designed interferometer, and the results agree well with the numerical simulations. Our study opens up the possibilities for generating, manipulating, and detecting MIR light that carries OAM, and will have great potential for optical communications and remote sensing in the MIR regime.

Manipulation of the orbital angular momentum via four-wave mixing in Rb vapor

“…However, the OAM conservation and Gouy phase matching indicate that it is mainly generated in the fundamental Gaussian mode. In addition, if a sapphire cell is used, the mode of the infrared beam can be directly observed [15,16,25].…”

“…Various nonlinear media provide possible venues for information transmission based on OAM transfer, such as crystals, atomic medium and two-dimensional materials [5,12,13]. Within these media, a wide range of nonlinear processes have been extensively investigated to realize the OAM transfer, including sum-frequency generation (SFG), four-wave mixing (FWM), and second-harmonic generation (SHG) [14][15][16]. In particularly, the OAM transfer based on FWM has attracted tremendous attention because the FWM process has strict phase matching conditions, which two (three) frequencies mutually interact to produce two (one) new frequencies, moreover, it prevents any information loss due to linear absorption and permits us to work at high optical depths [17][18][19].…”

Quantum entanglement and interference at 3 μm

“…For example, the common used semiconductor-based detectors and superconducting detection technologies face challenges in improving detection efficiency and signal-to-noise ratios, and system operation is highly dependent on deep cooling, making the detection system more complicate and expensive. An effective solution is to use spectral translation technology, i.e., upconversion of MIR signals into the visible or NIR region by means of nonlinear frequency transformations (33)(34)(35)(36)(37). The upconversion process can preserve the quantum properties of the photons and greatly reduce the effect from the ambient thermal background radiation on the detection.…”

Thermal camera based on frequency upconversion and its noise-equivalent temperature difference characterization

“…The use of high-performance detectors based on wide-bandgap materials (e.g., silicon) to detect MIR light after frequency conversion to visible/NIR light has proven to be an effective alternative 11 – 14 This technology has been rapidly developed in recent years, with better conversion efficiencies achieved using waveguides, 15 , 16 pulsed light, 17 , 18 and cavity enhancement schemes 19 , 20 . However, the upconversion process also introduces other noises into the detection results, so it is critical to analyze and evaluate the noise performance of the device.…”