High performance resonance Raman spectroscopy using volume Bragg gratings as tunable light filters

Abstract

We designed a near infrared tunable resonance Raman spectroscopy system based on a tandem of thick volume Bragg gratings (VBGs). VBGs are here the constituents of two light filtering units: a tunable laser line filter (LLF) and a tunable notch filter (NF). When adapted in a micro-Raman setup with a single stage monochromator (1800 gr/mm grating), the tandem of LLF and NF allowed measurements of Raman signals down to +/-20 cm(-1). The good performance and fast tunability of the VBG Raman system was demonstrated on a sulfur powder and on a bulk single-walled carbon nanotube sample through a series of 22 Stokes and anti-Stokes spectra recorded at excitation wavelengths between 800 and 990 nm. The main drawbacks of the setup are the limited spectral range to the near infrared and the small angular acceptance of the filters (approximately 1 mrad), which causes mainly attenuation problems with the NF. The impact of the main limitations is discussed and solutions are provided.

Photoluminescence from an individual double-walled carbon nanotube

“…The samples were mounted on a three-axis piezo-electric stage (PIMars P-563, Physik Instrumente) to ensure precise positioning and focusing of the laser spot. Incident excitations from various continuous-wave lasers were used: HeNe at 632.8 nm (1.96 eV), diode-pumped solid-state lasers at 457 nm (2.71 eV), 532 nm (2.33 eV), and 561 nm (2.21 eV), and a Ti:sapphire laser filtered using a tunable laser line filter [39] in the near infrared. To avoid heating effects, the laser intensity impinging the sample was kept below 100 kW/cm 2 .…”

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

“…[12,25]). The resonant Raman scattering measurements were performed with a homemade setup, including an iHR-550 Horiba spectrometer equipped with a liquid-nitrogen-cooled silicon CCD detector, with a wide variety of laser excitation wavelengths using Ar + , Kr + , and He-Ne lasers and tunable Ti:sapphire and dye lasers filtered using tunable laser line filters [26]. The scattered light was collected through a 100× objective (numerical aperture of 0.95) using a backscattering configuration.…”

Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes

“…The samples were mounted on a three-axis piezoelectric stage (PIMars P-563 PI) to ensure the precise positioning and focusing of the laser spot. Incident excitations from various continuous wave lasers were used: HeNe at 632.8 nm (1.96 eV), diode-pumped solid-state lasers at 457 nm (2.71 eV), 532 nm (2.33 eV) and 561 nm (2.21 eV), and a Ti-Sapphire filtered using a tunable laser line filter 53 in the near infrared. In all the measurements, the incident light polarization is along the nanotube axis.…”