Simple approach to one-laser, broadband coherent anti-Stokes Raman scattering microscopy

Abstract

Coherent anti-Stokes Raman scattering (CARS) microscopy is emerging as a powerful method for imaging materials and biological systems, partly because of its noninvasiveness and selective chemical sensitivity. However, its full potential for species-selective imaging is limited by a restricted spectral bandwidth. Recent increases in bandwidth are promising but still are not sufficient for the level of robust component discrimination that would be needed in a chemically complex milieu found, for example, in intracellular and extracellular environments. We demonstrate a truly broadband CARS imaging instrument that we use to acquire hyperspectral images with vibrational spectra over a bandwidth of 2500 cm(-1) with a resolution of 13 cm(-1).

Optical solitons from a photonic crystal fiber and their applications

“…11. In this figure, the CARS signal from a sample was normalized by the signal from a glass substrate to show the resonant contribution of CARS signal clearly (Kee & Cicerone, 2004). All results using a pulse shaper (quadratic, cosine, and pulse train phase patterns) agreed well and the Raman peaks observed by spontaneous Raman spectroscopy were observed clearly in CARS signals between 500 and 3100 cm −1 .…”

“…To generate a broadband optical pulse, a PCF can be used and only a single laser oscillator is required to observe a broadband CARS signal by the use of a PCF. The use of a PCF to generate broadband Stokes pulses was reported in 2003 (Paulsen et al, 2003) and since then, the extent of vibration frequencies has been extended (Kano & Hamaguchi, 2005;Kee & Cicerone, 2004). However, it is difficult to generate broadband pulses with uniform spectral intensities.…”

Single-shot hyperspectral coherent Raman planar imaging in the range 0–4200 cm−1

“…In order to utilize the entire spectral bandwidth available from the ultrashort timecompressed pulses and achieve maximum signal levels, temporal and spatial overlap of the pump/Stokes fields must be ensured. Ultrashort excitation demonstrated in single-beam CARS 25,26 and broadband/multiplex CARS 27,28 intrinsically achieves this requirement as variants of collinear phasematching. However, for imaging applications that require high spatial resolution, collinear CARS schemes need to be implemented with high numerical aperture using fast focusing optics 2 limiting applications to microscopy.…”

Detecting electronic coherence by multidimensional broadband stimulated x-ray Raman signals

“…Many spectroscopic techniques involve the creation and manipulation of coherences followed by a stimulated Raman detection of a probe pulse [1][2][3][4][5][6][7][8][9][10][11][12]. The field of multidimensional spectroscopy was launched by looking at the delays between impulsive stimulated Raman events [13].…”