Femtosecond Optical Bit Multiplication by Photon Echoes Excited with Spectrally Modulated Laser Pulses

Aleksander K. Rebane, Mikhail A. Drobizhev, Christophe Sigel +2 more

Georgy M. Safiullin, Victor G. Nikiforov, Vladimir S. Lobkov +2 more

The possibility to mechanize at room temperature a logical function of bit-to-bit parallel multiplication for optical echo-processor based on the third-order nonlinear optical response of a resonant medium is experimentally studied. The polyvinilbutural film doped with phthalocyanine dye was used as an operating medium in our experiments. The time needed to realize the logical operation, the result of which is presented in the spectrum of the nonlinear optical response of the medium after action of the two spectrally coded pumping pulses, is less than 1 ps. The values of a homogeneous broadening of S 0 – S 1 line Γ hom = 89 cm -1 and Γ hom = 44 cm -1 are established at T = 300 K and T = 77 K respectively. The laser excitation parameters needed for effective operating of optical processor are defined. The maximum word length achievable under current experimental conditions is estimated.

Hiroki Nakatsuka, Makoto Tomita, Masahiro Fujiwara +1 more

Vladimir S. Lobkov, S. V. Petrushkin, К. М. Салихов +3 more

The signals of primary and stimulated femtosecond photon echoes are investigated in a dye-doped polymer film at room temperature. The homogeneous S 0 → S 1 spectral line width, which is due to the interaction between the impurity molecules and the quasi-local low-frequency modes, is estimated (≈5 × 1012 Hz). Special attention is paid to the study of spectra of femtosecond echo signals. The short-wave shifts of these spectra, with respect to the spectrum of femtosecond exciting pulses, are observed. These shifts indicate that the anti-Stokes regime of femtosecond pulse emission is realized. Therefore, the coherent regime of laser cooling of solids appears to be possible. The prospects of using of this new cooling regime in the function of a solid-state optical refrigerator are discussed.

Wim H. Hesselink, Douwe A. Wiersma

Lap Van Dao, My Thi Tra Do, P. Eckle +1 more

The nonlinear optical properties of an undoped GaN epitaxial layer have been investigated in the spectral region 400 - 450 nm using two-colour multiple-pulse photon echo measurements. Variation of the laser wavelengths and pulse sequence and the use of spectrally resolved measurements allows us to study the dephasing of the donors and acceptors and the energy relaxation properties for the blue band of GaN