White-light laser

S. L. Chin, S. Petit, F. Borne, K. Miyazaki, The white light supercontinuum is indeed an ultrafast white light laser, Japanese Journal of Applied Physics 38, L126 (1999)... 

Atutov SN, Calabrese R, Grimm R, et al. "White-light" Laser Cooling of a Fast Stored Ion Beam. Physical Review Letters 1998 Mar 9 80(10) 2129-2132. 

For 2PA or ESA spectral measurements, it is necessary to use tunable laser sources where optical parametric oscillators/amplifiers (OPOs/OPAs) are extensively used for nonlinear optical measurements. An alternative approach, which overcomes the need of expensive and misalignment prone OPO/OPA sources, is the use of an intense femtosecond white-light continuum (WLC) for Z-scan measurements [71,72]. Balu et al. have developed the WLC Z-scan technique by generating a strong WLC in krypton gas, allowing for a rapid characterization of the nonlinear absorption and refraction spectra in the range of 400-800 nm [72]. 

Because on CCD setups excitation for D, S, and A images is usually filter-selected from a single white light source the relative intensity of excitation is approximately fixed. Confocal microscopes use separate laser lines, often from distinct lasers, that can (and for optimal imaging should) be independently adjusted. Thus, on CCD setups y (Eq. (7.6)) is constant for a given set of filters whereas on the confocal, it varies from image to image (also, see Sect. 7.4.2). 

In conventional chip experiments, fluorescence scanners are used for chip read-out. In the case of laser scanners, HeNe lasers are used as excitation sources and photomultiplier tubes as detectors, whereas CCD-based scanners use white light sources. The optical system can be confocal or non-confocal. Standard biochip experiments are performed using two fluorescent labels as... 

The choice of material for SG is very important and was first reported a decade ago by Brodeur and Chin [21, 75] using a femtosecond laser in condensed media. They observed that spectral broadening of the white light depends on the band-gap of the irradiated material [75]. Furthermore, they found the existence of a band gap threshold, 4.7eV, below which a medium... 

Fig. 5.8. Spectrum of white light obtained upon irradiation of BaF2. Note the extent and flatness in comparison with the corresponding spectrum measured for the incident laser beam...

To optimize the conversion efficiency, physical focusing conditions need to be optimized. With reference to the SG spectrum shown in Fig. 5.8, for fixed incident laser power and fixed focal length of the lens, the location of the focus point within the 7.5 cm long barium fluoride crystal was found to determine the extent of the white light spectrum. With the focus located f cm inside the crystal, the flattest possible spectrum of white light was obtained (as shown in Fig. 5.8), and the highest conversion efficiency was also achieved. 

---