S0-S1 two photon absorption dynamics of organic dye solutions

Penzkofer, Alfons; Leupacher, W.

doi:10.1007/bf02053662

Cited by 23 publications

(12 citation statements)

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“…If LJ\+W2 approaches an electronic transition, then Xxxxx{~^s5^15^2> _^i ) is sumfrequency enhanced. At resonance (uo x + LJ2 equal to an electronic transition frequency) two-photon absorption occurs [1,2,51], which reduces the pump pulse intensity. Some two-photon resonance enhancement of x^(-^SJ^SHJ^SH?-^i) is expected for the flint glass SF10, leading to larger (3Q values for the amplification process (II) (^SH + ^SH -> ^s + ^i) than shown in Fig.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Theoretical investigation of noncollinear phase-matched parametric four-photon amplification of ultrashort light pulses in isotropic media

Penzkofer

Lehmeier

1993

Opt Quant Electron

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The amplification of light signals (angular frequency UJS) in some isotropic media (D20, fused silica, and Schott type SF10 glasses) by noncollinear phase-matched parametric four-photon interaction u<\ + u 2 -> u$ + u\ is studied theoretically. Computer simulations are carried out for fundamental and second-harmonic pump pulses of a mode-locked Nd: glass laser. Degenerate interaction (wavelength A1=A2 = 1054nm or 527 nm) and nondegenerate interaction (A1= 1054nm/ A2 = 527nm) are considered. Characteristic phase-matching parameters and gain parameters versus wavelength are determined. Limitations by spectral bandwidth, optical absorption, optical damage, self-phase modulation, self-focusing and stimulated Raman scattering are analysed.

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Section: Numerical Simulationsmentioning

confidence: 99%

Theoretical investigation of noncollinear phase-matched parametric four-photon amplification of ultrashort light pulses in isotropic media

Penzkofer

Lehmeier

1993

Opt Quant Electron

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“…The absorption cross section at the second-harmonic wavelength A 2 = 527 nm is a 2 ~ 4.5 x 10 _19 cm 2 . The S 0 -S l transition is offresonant to the second-harmonic wavelength and therefore two-photon absorption does not influence third-harmonic generation [19,23,24]. The anomalous dispersion of the refractive index of the dye in the S x -absorption band allows phase-matching at a certain dye concentration.…”

Section: Dye and Solvent Characterizationmentioning

confidence: 99%

Phase-matched third-harmonic generation of Nd: Glass-laser picosecond pulses in a new cyanine-dye solution

et al. 1993

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Abstract. The phase-matched direct tripling of picosecond light pulses of a mode-locked Nd: glass laser in a new cyanine dye PMC is studied. The solvents trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) are applied. The S Q -S l absorption peak of the dye is around A = 480 nm and the absorption cross section at the third-harmonic wavelength of A 3 = 351.3 nm is only a 3 « 1 x 10~1 9 cm 2 . Phase-matching occurred at concentrations of C PM = 0.0874 mol/dm 3 in HFIP and 0.1088 mol/dm 3 in TFE. A third-harmonic energy conversion efficiency of r] E « 0.01 was achieved at a pump-laser peak intensity of I 0L « 2.5 x 10 11 W/cm 2 in a 5 mm long sample of PMC in TFE. The conversion efficiency is limited by destruction of phase-matching due to the intensity-dependent nonlinear refractive index of the dye solutions. PACS: 42.65Efficient frequency tripling of laser radiation is performed generally in a two-step process first generating the secondharmonic light in a phase-matched nonlinear optical crystal and then frequency mixing the fundamental and the secondharmonic light in another phase-matched nonlinear optical crystal [1][2][3]. The second-order nonlinear optical susceptibility x ( 2 ) is responsible for these conversion processes. Direct (single-step) angle-tuned phase-matched third-harmonic generation of Nd:laser radiation was realized in the crystals LiI0 3 [4], CaC0 3 [5], and /3-BaB 2 0 4 [6]. In the vapor phase efficient phase-matched third-harmonic generation of Nd: laser radiation was achieved in mixtures of alkali vapors and noble gases [2,[7][8][9][10][11][12][13]. The direct third-harmonic generation is caused by the third-order nonlinear optical susceptibility x (3) .Phase-matched third-harmonic generation of Nd: laser radiation in organic dye solutions was studied in [14][15][16][17][18][19]. Dyes having the S 0 -S l absorption peak between the fundamental and third-harmonic frequency were selected for a low absorption cross section at the third-harmonic frequency. They were dissolved in a solvent of low normal refractive index dispersion. Phase-matching was achieved at a certain dye concentration at which the anomalous refractive index dispersion of the dyes compensated the normal refractive index dispersion of the solvents. For the dye PYC dissolved in hexafluoroisopropanol the absorption cross section at the third-harmonic frequency v 3 was cr 3 = 3.55 x 10~1 8 cm 2 , the two-photon absorption cross section was a^l = 1.8 x 10~4 9 cm 4 s and the excitedstate absorption cross section of third-harmonic light was a 3 e x = 2.6 x 10~1 6 cm 2 [18]. A maximum third-harmonic energy conversion efficiency of r] E = 2 x 10 -4 was achieved for input peak intensities J 0 L > 10 11 W/cm 2 (sample thickness I = 0.2 mm) [18]. The maximum obtainable conversion efficiency was limited by i) the small interaction length because of residual dye absorption at the third-harmonic frequency and ii) by two-photon dye absorption at twice the fundamental laser frequency and concomitant excited-state absorption of the dye....

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“…The resulting high net gain generates a steeply rising intense pulse. The end of the laser action is due to the depletion of the upper laser level [10][11][12][60][61][62][63]. The steepness of the trailing edge of the generated pulse is determined by the photon-lifetime of the cavity, i cav ~ t R ßn{R2) (trailing hajif width ^ roundtrip time t R9 R2 is the reflectivity of output mirror M2) [63].…”

Section: Passive Q-switchingmentioning

confidence: 99%

“…Only low-gain active media have long upper laser level lifetimes and are suitable for Q-switched laser operation (ruby: T G Ä 3 ms; Nd:YAG: T g~2 50JIS, Nd:glass: T g^3 50|XS, alexandrite: T g~5 0 \is [63], C0 2 : TÄI ms for p~l mbar [61]). The energy storage capacity is limited approximately to the saturation energy density, wf = hvJ<r G , by the onset of amplified spontaneous emission [63] (ruby: High-gain active media (large a G , small T g ) are not suitable for Q-switching. For these media cavity dumping is used to generate intense short pulses [64].…”

Section: Passive Q-switchingmentioning

confidence: 99%

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Passive Q-switching and mode-locking for the generation of nanosecond to femtosecond pulses

Penzkofer

1988

Appl. Phys. B

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Abstract. The passive and hybrid Q-switching and mode-locking of solid-state lasers, dye lasers, semiconductor lasers and gas lasers is reviewed. The dynamics of saturable absorbers and reverse saturable absorbers is illustrated. The nanosecond pulse generation by passive and hybrid Q-switching of low-gain active media is described. The picosecond and femtosecond pulse generation by passive and hybrid mode-locking in low-gain and highgain active media is analysed. The performance data of passively and hybridly mode-locked cw femtosecond dye lasers are collected. The pulse shortening of ultra-fast pulses with saturable absorbers in intra-cavity and extra-cavity configurations is discussed. PACS: 42.55The photonic switching of lasers provides an important technique to generate short light pulses in the nanosecond to femtosecond time regime. The photons generated in the laser modify the transmission of the switching elements and cause the formation of short pulses. Saturable absorbers serve as intensity or energy dependent coupling elements in most cases. But occasionally intensity and energy-dependent refractive index changes have been applied. Nanosecond light pulses are generated in passively Q-switched lasers. The passive mode-locking of laser leads to the generation of nanosecond, picosecond or femtosecond pulse trains. The actual pulse durations depend on the spectroscopic data of the active media and of the passive elements.The nonlinear response of absorbers to light radiation is introduced in the next section [1][2][3][4][5][6][7][8][9]. The passive, and the hybrid Q-switching are discussed in . The passive, and the hybrid modelocking are described in Sect. 3. A distinction is made between the mode-locking of low-gain and high-gain active media [35 45]. The simultaneous Qswitching and mode-locking is discussed shortly in Sect. 4. A final section is devoted to the intra-cavity and extra-cavity pulse shortening with saturable absorbers [46][47][48][49][50].

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S0-S1 two photon absorption dynamics of organic dye solutions

Cited by 23 publications

References 40 publications

Theoretical investigation of noncollinear phase-matched parametric four-photon amplification of ultrashort light pulses in isotropic media

Theoretical investigation of noncollinear phase-matched parametric four-photon amplification of ultrashort light pulses in isotropic media

Phase-matched third-harmonic generation of Nd: Glass-laser picosecond pulses in a new cyanine-dye solution

Passive Q-switching and mode-locking for the generation of nanosecond to femtosecond pulses

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