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The nonlinear optical responses of perovskite films CsPbI2Br, MAPbI3 + 1% PVC, MA0.15FA0.75Cs0.1PbI2.85Br0.15, and MA0.15FA0.75Cs0.1PbI3, irradiated by femtosecond laser pulses with wavelengths of 1064 and 532 nm, are investigated using z-scan measurements. Nonlinear absorption is found to occur in perovskite films irradiated at a wavelength of 1064 nm; the nonlinear absorption coefficient in thin films (45 – 65 nm) greatly exceeds that in thick ones (120 – 350 nm): 524 – 928 and 38 – 50 cm GW−1, respectively. It is shown that the nonlinear absorption saturation intensity for perovskite films depends on the pump pulse duration and increases with pulse shortening. It is also established that the nonlinear absorption coefficient of organometallic perovskite films exceeds that of a film of inorganic perovskite CsPbI2Br. Bleaching of film samples during z-scanning at a wavelength of 532 nm is related to the irreversible photochemical degradation of films exposed to intense light. The kinetics of photochemical bleaching of the films is detected at a wavelength of 532 nm.

The thin MAPbI3 and MA0.15FA0.75Cs0.1PbI3 perovskite films have strong nonlinear absorption with coefficients of 443 ± 20 and 830 ± 50 cm GW–1, respectively, due to two-photon absorption at 1064 nm. The photochemical degradation of perovskite films was observed upon irradiation with femtosecond pulses at 532 nm, and the depth of photodegradation decreased in perovskite films protected with a PMMA polymer layer.

The use of a heavily doped germanosilicate fibre with a W-profile refractive index and small core diameter in stretchers of ultrashort laser pulses with their subsequent amplification and compression in all-fibre laser systems is considered. The application of fibres of this type makes it possible to stretch, amplify, and then compress a laser pulse with minimum distortions of its initial shape and width. Due to the dispersion properties of these fibres, which allow the pulse duration to be increased significantly at a small fibre length and the third-order positive dispersion of the diffraction-grating-based output compressor to be compensated for, amplified pulses with an energy of 2 μJ and width of 250 fs, free of a picosecond pedestal, are obtained. Several types of fibres intended for the use in stretchers of ultrashort laser pulses are comparatively analysed from the point of view of their dispersion compatibility with a diffraction-grating-based output compressor.

Nonlinear absorption of suspensions of graphene nanosheets with the number of layers from one to three was studied using the Z-scan method with femtosecond excitation at 1030 nm wavelength. A large modulation depth and lower saturation intensity of the suspensions as compared with nonlinear absorption of single-layer graphene were shown. Dynamics of photoexcited carriers for different duration of excitation pulse was considered. The values of the absorption cross section and the density of photoexcited carriers in single-layer graphene were estimated. The presence of two-photon absorption (TPA) in suspensions of graphene nanosheets and the absence of noticeable TPA in single-layer graphene were shown.

The nonlinear optical absorption of aqueous suspension with a few-layer (4–5 layers) molybdenum disulfide (MoS2) was investigated by Z- and P-scan methods using second harmonic generation from Yb-doped femtosecond pulsed laser. Two regions with different nature of the nonlinear absorption were registered when the intensity of the incident radiation increased from low to high values. The 3-level model for one-photon transitions in the few-layer MoS2 was proposed for describing the experimental data. Absorption cross sections and relaxation times for interband and intraband transitions under femtosecond excitation on 514 nm have been estimated.

Structural changes induced in fused silica subjected to focused femtosecond laser radiation in the heat accumulation regime are studied. The spatial profile of the induced refractive index and the effect its amplitude has on such effects as the self-focusing of the laser radiation, and thermal and photochemical processes are investigated. Individual contributions from each of these effects are separated and their effect is described on the basis of experimental dependences for the first time. It is also shown that the use of heat accumulation regime substantially increases the induced refractive index, compared to the nonthermal regime.

ProteoCat is a computer program that has been designed to help researchers in the planning of large-scale proteomic experiments. The central part of this program is the unit of hydrolysis simulation that supports 4 proteases (trypsin, lysine C, endoproteinases Asp-N and GluC). For peptides obtained after virtual hydrolysis or loaded from data files a number of properties important in mass-spectrometric experiments can be calculated and predicted; the resultant data can be analyzed or filtered (to reduce a set of peptides). The program is using new and improved modifications of own earlier developed methods for pI prediction, which can be also predicted by means of popular pKa scales proposed by other reseachers. The algorithm for prediction of peptide retention time has been realized similarly to the algorithm used in the SSRCalc program. Using ProteoCat it is possible to estimate the coverage of amino acid sequences of analyzed proteins under defined limitation on peptides detection, as well as the possibility of assembly of peptide fragments with user-defined minimal sizes of “sticky” ends. The program has a graphical user interface, written on JAVA and available at http://www.ibmc.msk.ru/LPCIT/ProteoCat.

The investigation of a thermal breakdown at cumulative regime in fused silica is reported. Assumptions about the cause and method of avoidance are made.

This paper describes an all-normal-dispersion pulsed ytterbium-doped fibre ring laser mode-locked by a nonlinear combined modulator based on single-wall carbon nanotubes. We have demonstrated 1.7-ps pulse generation at 1.04 μm with a repetition rate of 35.6 MHz. At the laser output, the pulses were compressed to 180 fs. We have examined an intracavity nonlinear modulator which utilises nonlinear polarisation ellipse rotation in conjunction with a saturable absorber in the form of a polymer-matrix composite film containing single-wall carbon nanotubes.

Ultrafast pulse generation in all-normal dispersion Yb-doped fiber laser on 1.04 μm have been reported. Stable self-starting pulse generation in output of the ring fiber laser have been investigated where nonlinear polarization rotation interacted with contribution from the single walled carbon nanotube saturable absorber. Laser pulses with 0.7 nJ pulse energy and 1.7 ps pulse width at 35.6 MHz repetition rate were achieved. The output pulse could be externally compressed to width of 180 fs by pair of gratings.

The operation regimes of a pulsed all-normal-dispersion polarisation-maintaining fibre laser with a nonlinear optical loop mirror are studied. The use of polarisation-maintaining fibres ensures polarisation and temperature stability of output radiation. The lasing and instability thresholds of the pulsed laser are determined experimentally. A spectral filter placed in the cavity makes it possible to change the centre wavelength of laser radiation within the range 1.02 – 1.05 μm with a spectral full width at half maximum of 2 nm. The average output power is 7 mW, which corresponds to a pulse energy of 0.8 nJ. The autocorrelation function width of the output pulse is 50 ps. The minimum pulse duration achieved after compression by an external pair of diffraction gratings is 1.8 ps. The dynamics of the temporal and spectral parameters of laser pulses is studied using mathematical simulation based on numerical solution of the nonlinear Schrodinger equation. The simulation results coincide with experimental data with a high accuracy.

We investigated refractive index induced by direct femtosecond laser writing inside fused silica and Nd:phosphate glass in heat accumulation regime. Spatial profile and magnitude of induced refractive index were investigated at various pulse repetition rates and translation velocities. It was shown that the magnitude of induced refractive index significantly rises with decreasing in time interval between successive laser pulses below the time for thermal diffusion. Going from nonthermal regime to heat accumulation regime, we achieved induced refractive index growth from 4 × 10−3 up to 6.5 × 10−3 in fused silica and from −6 × 10−3 to −9 × 10−3 in Nd:phosphate glass. Aspect ratio of treated area decreased from 2.1 down to less than 1.5 without correcting optical elements. It was shown that in heat accumulation regime, the treated area was surrounded by region of alternatively changed refractive index with significant magnitude up to −2 × 10−3. Wide regions of decreased refractive index enable fabrication of depressed cladding waveguides. We demonstrated low-loss (0.3 dB/cm) tubular waveguide inside fused silica. For orthogonal polarizations of guiding light, we achieved a small difference between losses as 0.1 dB/cm using highly symmetric written tracks forming the cladding. The desired structure was simulated with the beam propagation method, and the results were in good agreement with experiment data.

The data on approximate values of isoelectric point (pI) of peptides obtained during their fractionation by isoelectric focusing can be successfully used for the calculation of the pKa's scale for amino acid residues. This scale can be used for pI prediction. The data of peptide fractionation also provides information about various posttranslational modifications (PTM), so that the prediction of pI may be performed for a wide range of protein forms. In this study, pKa values were calculated using a set of 13448 peptides (including 300 peptides with PTMs significant for pI calculation). The pKa constants were calculated for N-terminal, internal and C-terminal amino acid residues separately. The comparative analysis has shown that our scale increases the accuracy of pI prediction for peptides and proteins and successfully competes with traditional scales and such methods as support vector machines and artificial neural networks. The prediction performed by this scale, can be made in our program pIPredict with GUI written in JAVA as executable jar-archive. The program is freely available for academic users at http://www.ibmc.msk.ru/LPCIT/pIPredict. The software has also the possibility of pI predicting by some other scales; it recognizes some PTM and has the ability to use a custom scale.Dannye o priblizitel'nom znachenii pI, poluchennye v khode fraktsionirovaniia peptidov metodom izoélektricheskogo fokusirovaniia, mogut byt' s uspekhom ispol'zovany dlia rascheta shkaly znacheniĭ pKa aminokislotnykh ostatkov, na osnovanii kotoroĭ mozhno predskazat' pI dlia liubogo proizvol'nogo peptida. Takogo roda dannye soderzhat informatsiiu o razlichnykh posttransliatsionnykh modifikatsiiakh (PTM), blagodaria chemu predskazaniia pI mogut byt' osushchestvleny dlia shirokogo spektra belkovykh form. V nastoiashcheĭ rabote raschet shkaly znacheniĭ pKa proveden na osnovanii vyborki v 13448 peptidov, 300 iz kotorykh imeli PTM znachimye dlia rascheta pI. Konstanty dlia N-kontsevykh i C-kontsevykh aminokislotnykh ostatkov uchityvalis' samostoiatel'no. Sravnitel'nyĭ analiz pokazyvaet, chto ispol'zovanie nasheĭ shkaly povyshaet tochnost' predskazaniia pI kak dlia peptidov, tak i dlia belkov, s uspekhom konkuriruia kak s traditsionnymi shkalami, tak i s uzkospetsializirovannymi metodami predskazaniia, takimi kak metody opornykh vektorov i iskusstvennykh neĭronnykh seteĭ. Ispol'zovat' dannuiu shkalu dlia predskazaniia pI mozhno s pomoshch'iu razrabotannoĭ nami programmy s graficheskim interfeĭsom, napisannoĭ na iazyke JAVA v vide ispolniaemogo jar-arkhiva. Programma svobodna dlia ispol'zovaniia akademicheskimi pol'zovateliami i dostupna po adresu http://www.ibmc.msk.ru/LPCIT/pIPredict. V programme realizovany takzhe vozmozhnosti predskazaniia po riadu drugikh shiroko rasprostranennykh shkal, ucheta nekotorykh PTM i dobavleniia sobstvennykh variantov shkaly.

Saturable absorption (SA) of film composites based on carboxymethylcellulose (CMC) polymer with single-walled carbon nanotubes (SWNTs) and graphene (GR) was studied by the Z-and P-scan methods with femtosecond probing pulses at a wavelength of 1.06 μm. The values of the saturation intensities for composites GR-CMC and SWNT-CMC were determined. The optical and thermal damage thresholds of the composites were measured. Q-switching stability limits for passive mode locking in fiber laser with SWNT-CMC SA were analyzed.

Direct femtosecond laser inscription has become an advanced and widespread maskless technology for waveguides writing inside optical materials. One of the advantages of the technology consists in combination of both high efficiency of integral optics and perfect thermal and spectral characteristics of bulk optical elements. In the paper we proposed, for what is believed to be the first time, femtosecond inscription of induced structures with modified refractive index (reduced down to −6 × 10−3) within significantly broad depth range (more than 550 μm) and waveguide with mode field diameter 200 μm, 30 mm length and numerical aperture 0.04. Proposed result broadens field of application of femtosecond writing technology into large mode diameter waveguides formation and hybrid integral-bulk laser schemes that create an opportunity to develop novel optical elements. Laser induced tracks with controlled refractive index were written with aspherical lens at all the depths within range between 550 and 1100 μm under the surface of the sample. Continuous writing process at significantly different depths was based on dynamic adjustment of femtosecond pulses energy to compensate negative effect of spherical aberration. In the investigation we examined dependences of writing energy range and geometry of induced refractive index tracks on writing depth. Experiments were carried out in Nd:phosphate glass in thermal cumulative regime (repetition rate of femtosecond pulses was 2 MHz) and compared with numerical simulation. It was shown, that dependence of working range on focusing depth is nonlinear, nonmonotonic and significantly differs for positive and negative shift from optimal correction depth of the lens.

The application of a fiber with W-type refractive index profile as a stretcher of ultrashort laser pulses for chirped pulse amplification is shown. As a result, pulses were obtained with energy of 3 µJ and duration of 270 fs, with high pulse contrast due to dispersion compatibility of the fiber stretcher and compressor on diffraction gratings. A comparative analysis of several types of fibers for use as a stretcher for amplification of chirped pulses is given in terms of their compatibility with the compressor.

High-spin intermediates with S = 2 generated by γ-radiolysis of triazidopyridines at 77 K were studied using the ESR method in the X range. Their thermal stability at 77–240 K with the transition to the one-electron states (S = 1/2) due to intermolecular reactions at 100–200 K was shown. The study of saturation processes elucidated an effect of a sharp nonlinear increase in the intensity of the ESR signals from quintet dinitrenes with an increase in the microwave field power higher than 10 mW. This effect can be applied as a method of identification of high-spin molecules obtained together with other paramagnetic products of low multiplicity and in the search for systems with molecular magnetism. A set of principles was developed for making compact undulators based on static molecular magnetic structures using dynamic effects upon the interaction of an electron beam with a laser pulse counter.

The review of femtosecond laser installations for medical applications is given and a new femtosecond ophthalmologic system for creation of a flap of corneal tissue during the LASIK operation is described. An all-fibre femtosecond laser emitting ~400-fs pulses at 1067 nm is used. The pulse repetition rate can vary from 200 kHz up to 1 MHz. The output energy of the femtosecond system does not exceed 1 μJ. A specially developed objective with small spherical and chromatic aberrations is applied to focus laser radiation to an area of an eye cornea. The size of the focusing spot does not exceed 3 μm. To process the required area, scanning by a laser beam is applied with a speed no less than 5 m s-1. At a stage of preliminary tests of the system, the Κ8 glass, organic PMMA glass and specially prepared agarose gels are used as a phantom of an eye. The femtosecond system is successfully clinically tested on a plenty of eyes of a pig and on several human eyes. The duration of the procedure of creation of a corneal flap does not exceed 20 s.

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.

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.

Correction Y-branches power dividers of the multi-function integrated optics chips on proton-exchanged waveguides in lithium niobate by the technology of direct femtosecond laser writing were investigated. Optimal correction parameters and their influence on temperature stability of Y-splitter are determined. Keywords: lithium niobate, Y-splitters, proton exchange, femtosecond writing, refractive index, integrated optics.

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.

Algorithm for the mathematical modelling of a fiber oscillator with a hybrid modulator based on a nonlinear fiber mirror and single-walled carbon nanotubes is suggested. It is based on a numerical solution of the nonlinear Schrodinger equation. Using numerical simulation, optimum NOLM coupler ratio, laser spot diameter on the sample preventing sample degradation and high modulator effect are determined.It is shown that hybrid modulator accelerates the self-starting process and decreases the output pulse duration up to 10%.

The relaxation of the Q1(π—π*) excited state of the nonprotonated Fc4PH2 and diprotonated Fc4PH4 2+ forms of meso-tetraferrocenylporphyrin was studied by femtosecond laser absorption spectroscopy. Transition from the Q1(π—π*) state to the charge-transfer state was shown to occur within 208±10 fs for Fc4PH2 and 9±3 ps for Fc4PH4 2+. A fast vibrational relaxation with a characteristic time of 120—140 fs was found for both forms. The relaxation time of Fcδ+—Pδ– charge-transfer state for Fc4PH2 was 17±4 ps.

The results of an experiment on the time-resolved spectral dynamics of the eosin phosphorescence in a low-temperature glycerol–water mixture are explained supposing a cluster structure of the supercooled liquid and the glass. An estimation of the size and the restructurization dynamics time of the clusters at about 237 K are performed. A modification concerning the procedure for the calculation of the relaxation function of a time-resolved spectral shift obtained in a supercooled liquid, possessing a cluster structure, is suggested. A conclusion on the existence of a new amorphous phase is inferred from the change in the spectral dynamics of the eosin phosphorescence observed in the low-temperature mixture.

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.

The kinetics of the formation and decay of photoexcited radical ion pairs of donoracceptor charge-transfer complexes between C60 andN,N-diethylaniline (DEA) in chlorobenzene was studied by picosecond laser-induced diffraction gratings. It was established that the anisotropy of polarization of the diffraction signal decreases as the concentration of DEA increases. The radical ion states of the photoexcited C60−...DEA+ complex have zero anisotropy. This effect is likely due to the isotropic intracomplex transfer of an electron from the local excited state to the radical ion state. The rate constant of quenching of the singlet excited C60 byN,N-diethylaniline (1.4·1010 L mol−1 s−1) and the lifetimes of the solventseparated C60−...DEA+ and tight [C60−...DEA+] (95±7 and 31±4 ps, respectively) radical ion pairs were measured.

Anisotropy time dependence of photoexcited C50 and C70 has been measured by picosecond transient grating techniques at room temperature in various solvents. The monoexponential anisotropy decay was observed for the C60 molecule and biexponential anisotropy decay was observed for the C70 molecule. Both for the C60 and for the C70 molecules anisotropy time decay is very fast. The data obtained were analyzed in terms of the rotational reorientation of fullerene molecules in solvents. Hynes-Kapral-Weinberg theory reasonably explains the observed reorientation times of fullerenes molecules. The dielectric friction effect on the C70 rotational reorientation on the short axis is reported.

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.

A novel technique was proposed for 3D femtosecond writing of waveguides and optical integrated circuits in the presence of strong spherical aberration, caused by inscription at significantly different depth under the surface of optical glasses and crystals. Strong negative effect of spherical aberration and related asymmetry of created structures was reduced due to transition to the cumulative thermal regime of femtosecond interaction with the material. The differences in the influence of spherical aberration effect in a broad depth range (larger than 200 µm) was compensated by dynamic adjustment of laser pulse energy during the process of waveguides recording. The presented approach has been experimentally implemented in fused silica. Obtained results can be used in production of a broad class of femtosecond written three-dimensional integrated optical systems, inscripted at non-optimal (for focusing lens) optical depth or in significantly extended range of depths.

We demonstrated two stable pulsed operation regimes of all-polarization maintaining (PM) Yb-doped fiber laser oscillator with pulse duration of 640 and 85 ps. Nonlinear optical loop mirror (NOLM) was used for laser mode-locking. The first operation regime delivered high energy pulses of 5 nJ, and second regime delivered pulses of 0.7 nJ at a common repetition rate 5 MHz. The dynamics of the temporal and spectral parameters of laser pulses was studied using mathematical simulation based on numerical solution of the nonlinear Schrodinger equation. The simulation results showed that in stable regime with pulse duration of 85 ps the pulse could be compressed to 2 ps.

We demonstrated technique of direct femtosecond waveguide writing at record low depth (2-15 μm) under surface of lithium niobate, that play a key role in design of electrooptical modulators with low operating voltage. To prevent optical breakdown of crystal surface we used high numerical aperture objectives for focusing of light and non-thermal regime of inscription in contrast to widespread femtosecond writing technique at depths of tens micrometers or higher. Surface optical breakdown threshold was measured for both x- and z- cut crystals. Inscribed waveguides were examined for intrinsic microstructure. It also reported sharp narrowing of operating pulses energy range with writing depth under the surface of crystal, that should be taken in account when near-surface waveguides design. Novelty of the results consists in reduction of inscription depth under the surface of crystals that broadens applications of direct femtosecond writing technique to full formation of near-surface waveguides and postproduction precise geometry correction of near-surfaces optical integrated circuits produced with proton-exchanged technique.

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.

The kinetics of relaxation of optical anisotropy induced by polarized light in endometallofullerenes La@C2n inortho-dichlorobenzene was studied by picosecond laser photolysis. Decay of the optical absorption signal due to the excited states of La@C2n follows the biexponential law with two values of relaxation time:t1=35±3 ps andt2=1100±200 ps. The lifetimet or decay of the optical anisotropy is 19±5 ps and determined by the orientational diffusion of La@C2n. The experimentally determined lifetime of optical anisotropy agrees satisfactorily with the value yielded by the theoretical model of orientational diffusion under slip boundary conditions at the interface of the La@C2n molecule with the solvent.

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.

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.