Multiple- and single-shot autocorrelator based on two-photon conductivity in semiconductors

Area of Science:

• Optoelectronics
• Nonlinear Optics
• Semiconductor Physics

Background:

• Ultrashort optical pulse measurement is crucial for various scientific and technological applications.
• Traditional methods for pulse measurement can be complex and expensive.

Purpose of the Study:

• To investigate and apply two-photon-induced conductivity for ultrashort optical pulse measurements.
• To demonstrate a simplified and cost-effective measurement technique.

Main Methods:

• Observed two-photon-induced conductivity in Silicon (Si), Gallium Arsenide Phosphide (GaAsP) photodiodes, and Cadmium Sulfide (CdS) photo-conductive cells.
• Utilized a simplified Michelson-type interferometer arrangement.
• Employed a two-dimensional Silicon Charge-Coupled Device (CCD) array for single-shot pulse-width measurements.

Main Results:

• Achieved two-photon conductivity with an efficiency of 3 x 10^-14 A/W (where I is incident pulse intensity in W/cm^2).
• Successfully performed single-shot pulse-width measurements.
• Demonstrated the convenience of inexpensive photodetectors with nonlinear characteristics.

Conclusions:

• Two-photon conductivity in Si and semiconductor devices is a viable method for ultrashort optical pulse measurement.
• The proposed technique is convenient, cost-effective, and offers an instantaneous response.
• This method is well-suited for intensity correlators and optical pulse characterization.