Visible and near-infrared Fourier transform spectroscopy with a common-path interferometer

Abstract

Optical spectrometers can be generally divided into two categories, frequency-domain and time-domain ones. The former includes compact, industrial-grade instruments that are easily available in the visible spectral range. The latter are lab-grade, bulky and fragile instruments that offer very high sensitivity and accuracy but are mainly limited to the infrared spectral region. This manuscript aims to present a time-domain device and several of its applications in which it is possible to combine some of the advantages of the two techniques, finally, bringing the advantage of Fourier transform spectroscopy down to the visible and near-infrared spectral regions. The device is a common-path interferometer based on birefringence. The concept is straightforward, and it is a compact, robust, and cost-effective instrument, and it has been applied in a wide range of applications. In this manuscript, the interferometer will be described from a theoretical point of view, and its capabilities will be presented applied to the measurement of fluorescence excitation-emission matrix maps down to the ultimate sensitivity at the single-molecule level, time-resolved photoluminescence spectra, spectral images, and the complex optical activity.

Optical Properties and Ultrafast Near‐Infrared Localized Surface Plasmon Dynamics in Naturally p‐Type Digenite Films

“…Two different spectral regions were inspected in the infrared between 1200 and 1750 nm using white light obtained from a 1-cm-long YAG and visible range between 530 and 730 nm exploiting pulses generated in a 4-mm-long YAG. [42] The detection system consisted of an interferometric spectrometer based on a birefringent delay line (GEMINI, Nireos), [43][44][45][46] followed by two different detectors, depending on the spectral region of interest. Measurements in the infrared were performed using an amplified thermoelectrically cooled InAsSb detector (PDA10PT, Thorlabs) sensitive between 1000 and 5800 nm, while those in the visible exploited a Si biased photodiode (DET100A2, Thorlabs) connected to a transimpedance amplifier.…”

Time gated Fourier transform spectroscopy with burst excitation for time-resolved spectral maps from the nano- to millisecond range

“…The time delay is controlled by moving a birefringent wedge pair a distance, x. Fourier transforming (FT) the recorded interferogram and performing a series of calibrations yields the corresponding emission spectrum (I(l)). 18 By combining TCSPC with the TWINS interferometer, it is possible to record 2D temporal-spectral maps, which has previously been demonstrated in the micro-time domain. 16,19,20 In the micro-time domain, it is possible to temporally disentangle spectrally overlapping signals with ease if their decay times are sufficiently distinct (e.g., a short-lived state of 1 ns and a longlived state of 1 ms).…”

“…The working principle of the TWINS interferometer has been described in detail previously. 18 Briefly, the TWINS interferometer is positioned in the emission path, and luminescence is passed through it. In the TWINS interferometer, the two polarization components of the emission light travel on the same path but will inhere a delay due to the birefringent medium.…”

“…Fourier transforming (FT) the recorded interferogram and performing a series of calibrations yields the corresponding emission spectrum ( I ( λ )). 18…”