 | Wave packet engineering using a phase-programmable femtosecond optical source
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| | I. Matsuda1), K. Misawa1) and R. Lang1) |
| | 1) Tokyo University of Agriculture and Technology |
| | A phase-programmable femtosecond optical source is indispensable for interactive control of photonic and electronic wave packets. In the present paper, we describe wave-packet shaping in the excited state of organic dye molecules. The phase-programmable femtosecond optical source is composed of a femtosecond pulse oscillator, phase modulator and phase analyzer as shown in Fig.1[1]. A femtosecond pulse with a spectral band width as broad as 100 nm is converted onto the Fourier plane. After a phase shift is provided to each spectral component by a spatial light modulator on the Fourier plane, the pulse is reconstructed. The output from the phase modulator is characterized by frequency resolved optical gating (FROG). The temporal profile and phase information of the femtosecond pulses can be obtained from the FROG measurement. A desired phase pattern can be realized through the iterative adjustment of the phase mask by analyzing the phase information. Figure 2 show the spectrum and phase dispersion for positively-chirped (Φ''(ω)=500 fs2), transform-limited (0 fs2) and negatively-chirped pulses (−500 fs2). |
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