Dmitry V. Khudyakov

Nonlinear optical absorption of single-wall carbon nanotubes in carboxymethylcellulose thin polymerfilm and its application as a saturable absorber for mode-locking in pulsed Nd:glass laser

Nonlinear optical absorption of single-wall carbon nanotubes in carboxymethylcellulose (CMC) thin polymer film has been studied by the Z-scan method. Nonlinear saturated absorption at lambda=1080 nm was registered with saturation intensity of 170 MW/cm(2). Ultrashort pulses with duration of 3 ps were generated at lambda=1055 nm using this composite polymer film as a saturable absorber for passive mode locking in a neodymium glass laser.

Passive mode locking in a Ti:sapphire laser using a single-walled carbon nanotube saturable absorber at a wavelength of 810 nm

We report mode locking in a Ti:sapphire (Ti:Sa) laser at the wavelength of 810 nm using a polymer film with single-walled carbon nanotubes (SWNTs) applied as a saturable absorber. Pulses with 600 fs duration and 0.4 nJ energy were generated from the Ti:Sa laser with polymer-SWNT composite film for cw passive mode locking.

Saturable absorption of film composites with single-walled carbon nanotubes and graphene

Saturable absorption of polymer film composites with single-walled carbon nanotubes (SWNTs) and multilayer graphene (GR) were studied by Z- and P-scan methods with femtosecond probing pulses at a wavelength of 1.06 μm. As a matrix for the composite film, a polymer carboxymethylcellulose (CMC) was used. For these composites, the dependence of transmittance on peak intensity of a probe pulse was shown. The values of saturation intensities for the GR-CMC and SWNT-CMC composites were determined by the different methods. The intensities at which optical damage of the composites occurs were estimated.

Poor fluorinated graphene sheets carboxymethylcellulose polymer composite mode locker for erbium doped fiber laser

We report poor fluorinated graphene sheets produced by thermal exfoliation embedding in carboxymethylcellulose polymer composite (GCMC) as an efficient mode locker for erbium doped fiber laser. Two GCMC mode lockers with different concentration have been fabricated. The GCMC based mode locked fiber laser shows stable soliton output pulse shaping with repetition rate of 28.5MHz and output power of 5.5 mW was achieved with the high concentration GCMC, while a slightly higher output power of 6.9 mW was obtained using the low concentration GCMC mode locker.

Nonlinear Optical Absorption of Nanocomposite Films Made from Polymers and Single-Walled Carbon Nanotubes: The Effect of Nanotube Type and Polymer Matrix

Nonlinear optical absorption at a wavelength of 1080 nm for nanocomposite thin films made from polymers and single-walled carbon nanotubes (SWNTs) was studied by the longitudinal scanning (z-scan) technique. Two SWNT types differing in the synthesis procedure (HipCO and arc evaporation techniques) were used for the preparation of nanocomposites based on the polymers carboxymethylcellulose (CMC) and poly(vinyl alcohol) (PVAL). The nonlinear absorption coefficients were measured to be −5.0 × 10−7 and −3.9 × 10−7 cm/W for the CMC-SWNT/HipCO and CMC-SWNT/Arc composite films and −1.7 × 10−7 and −0.9 × 10−7 cm/W for the PVAL-SWNT/HipCO and PVAL-SWNT/Arc films, respectively. It was found that the film nanocomposites based on carboxymethylcellulose had a higher absolute value of the nonlinear absorption coefficient than the films in which PVAL was used as the polymer matrix.

Femtosecond pulse excitation of vibrational wave packets in chloroform: The effect of gold nanoparticles

Excitation of pure chloroform or a gold colloid in chloroform (average nanoparticle diameter of 2.5 nm) with 740-nm femtosecond pulses of 23-fs duration leads to oscillations in the differential absorption signal ΔA(λ, t) recorded using white-light continuum. The main oscillation modes for both systems are close to the chloroform Raman resonance frequencies of 260, 367, and 668 cm−1. However, marked narrowing and splitting of bands in the Fourier-transform spectra of oscillations are observed in the system of gold colloid in chloroform. The intensity of oscillations linearly increases with the pump pulse intensity in the cases of pure chloroform and the system of gold colloid in chloroform. Apparently, the principal mechanism of excitation of coherent packets in chloroform is femtosecond impulsive stimulated Raman scattering (ISRS). Dissolution of gold nanoparticles leads to a four- to sixfold enhancement of the Raman resonance signal of chloroform in the gold colloid as compared with pure chloroform. The increase in the intensity of Raman resonances is presumably due to amplification in the near field of gold nanoparticles.

Use of a film modulator with single-walled carbon nanotubes for mode locking in a pulse titanium-sapphire laser at a wavelength of 810 nm

The feasibility of mode locking in a pulsed laser at a wavelength of 810 nm was shown when a carboxymethylcellulose film with single-walled carbon nanotubes was used as a saturable absorber. With the use of such a film modulator for passive mode locking in the titanium-sapphire laser, a train of continuous-wave ultrashort pulses was obtained. The energy and the duration of a single pulse in the train were 0.4 nJ and 600 fs, respectively.

Ultrashort pulse generation in a neodymium glass laser with a nanocomposite film of carboxymethyl cellulose and single-wall carbon nanotubes as a saturable absorber for passive mode locking

Stable generation of ultrashort pulses is achieved in a neodymium glass laser with a nanocomposite film of a carboxymethyl cellulose (CMC) polymer and single-wall carbon nanotubes (SWNTs) used as saturable absorber for passive mode locking. A thin CMC-SWNT film placed in a laser resonator made it possible to generate ultrashort pulses of 3 ps at a wavelength of 1055 nm with a 15 μJ output single pulse energy in flashlamp pumped mode.