P.K. Palanisamy

Z-SCAN DETERMINATION OF THE THIRD-ORDER OPTICAL NONLINEARITY OF ORGANIC DYE NILE BLUE CHLORIDE

The single beam Z-scan technique was used to determine the nonlinear optical properties of the organic dye Nile Blue chloride in the solvent ethanol. The experiments were performed with a He-Ne laser with a wavelength of 632.8 nm. The negative nonlinear refractive index and two-photon absorption coefficient were observed in this dye. The intensity-dependent nonlinear refractive index was investigated. The result shows that the dye exhibits a great nonlinear response with the real and imaginary parts of the third-order nonlinear optical susceptibility χ(3) being -4.12×10-5 esu and 1.35×10-6 esu, respectively. These results show that the Nile Blue chloride dye has potential applications in nonlinear optics.

Nd:YAG laser pumped energy transfer distributed feedback dye laser in Rhodamine 6G and Acid blue 7 dye mixture

Abstract The characteristics of Nd:YAG laser pumped energy transfer distributed feedback dye laser (ETDFDL) is studied theoretically and experimentally in a mixture of Rhodamine 6G and Acid blue 7 dyes. The characteristics of donor DFDL, the acceptor DFDL, the dependence of their pulse width and output power on donor–acceptor concentrations, pump power and lengths of the excited region are studied. Experimentally the output energy of DFDL is measured at the emission peak of donor and acceptor for different pump powers, donor, acceptor concentrations and length of the active medium. In addition, the tunability of DFDL emission both in donor and acceptor emission ranges is measured.

Studies on widely tunable ultra-short laser pulses using energy transfer distributed feedback dye laser

Abstract This paper presents both theoretical and experimental study of the characteristics of Nd: YAG laser pumped energy transfer distributed feedback dye laser (ETDFDL). Using theoretical model proposed, the behavior of ETDFDL such as the characteristics of donor DFDL, the acceptor DFDL, the dependence of their pulse width and output power on donor–acceptor concentrations and pump power are studied for dye mixture Rhodamine 6G and Cresyl Violet in detail. Experimentally using prism-dye cell configuration, the ETDFDL output is obtained and the output energy of DFDL is measured at the emission peaks of donor and acceptor dyes for different pump powers and donor–acceptor concentrations. In addition, the DFDL linewidth measurement has been carried out at the lasing wavelengths of the donor and acceptor dyes using Fabry–Perot etalon and the tunability of DFDL is measured to be in the wavelength range of 545– 680 nm .

A new optical configuration in speckle interferometry for contouring of three-dimensional objects

A novel optical configuration for contouring of three-dimensional objects is presented. In this configuration (referred to as image plane speckle interferometry) an object point is viewed symmetrically with respect to the surface normal and combined coherently at the image plane of the imaging system. This configuration is simple to implement and provides the possibility to vary the sensitivity over a wide range. Detailed theory and experimental results are presented.

Energy transfer distributed feedback dye laser using Rhodamine B–Acid blue 7 dye mixture

The characteristics of energy transfer distributed feedback dye laser (ETDFDL) are studied both theoretically and experimentally in a mixture of Rhodamine B and Acid blue 7 dyes pumped by 532 nm Nd:YAG laser. The behaviour of donor and acceptor DFDL, the dependence of their pulse width and output power on pump power and donor-acceptor concentrations are studied. Experimentally, the tunability is achieved over the spectral range 565-680 nm using a prism dye cell arrangement. The output energy of DFDL is measured at the emission peaks of donor and acceptor for different pump powers and donor-acceptor concentrations. The output pulse of DFDL is found to be as narrow as 40-ps duration, which is nearly 100-fold shorter than the pump pulse. The pulse linewidth is of the order of 0.1 A.

Tunable picosecond energy transfer distributed feedback dye laser using Rhodamine 6G and Thionine dye mixture

The characteristics of Nd:YAG laser pumped energy transfer distributed feedback dye laser (ETDFDL) is studied both theoretically and experimentally. Using theoretical model proposed the behaviour of ETDFDL for dye mixture Rhodamine 6G and Thionine is studied in detail. The characteristics of donor DFDL, the acceptor DFDL, the dependence of their pulse widths and output powers on donor–acceptor concentration and pump power are studied. The output energy of DFDL is measured experimentally at the emission peaks of donor and acceptor dyes for different pump powers and donor–acceptor concentrations. In addition, the tunability of DFDL emission is measured both in donor and acceptor emission ranges.

Tunable ultrashort pulse energy transfer distributed feedback dye laser

This paper presents the characteristics of energy transfer distributed feedback dye laser (ETDFDL) in a mixture of Rhodamine B (RhB) and Thionine (Th) dyes pumped by 532 nm Nd:YAG laser both theoretically and experimentally. The characteristics of donor DFDL, the acceptor DFDL, the dependence of their pulse widths and output powers on donor-acceptor concentrations and pump power are studied. Experimentally the output energy of DFDL is measured at the emission peaks of donor and acceptor dyes for different pump powers, donor-acceptor concentrations and the tunability is observed from 565 nm to 665 nm using prism dye cell arrangement.

Pulse shortening utilizing acceptor dye as saturable absorber in energy transfer distributed feedback dye laser

In this paper, a simple method of pulse narrowing by double Q-switching is presented. In energy transfer distributed feedback dye laser (ETDFDL) when acceptor dye acts as a saturable absorber, pulse narrowing is observed in both donor and acceptor emission regions. In prism-dye cell configuration using second harmonic of Nd-YAG laser as pump source, the ETDFDL output is obtained from dyes Rhodamine 6G (R6G) as donor and Acid Blue 7 (Ab7)/Thionine (Th) as acceptors. In Rhodamine 6G and Acid Blue 7 combination pulse narrowing is observed only in the acceptor region whereas in the other combination namely Rhodamine 6G and Thionine, it is observed in both donor and acceptor regions. This is because of good overlap of the emission spectra of donor with the absorption spectra of acceptor. The detailed study is presented in this paper.