The Research Of Real-time Ultrafast Phenomenon Detection Based On Pulsed Digital Holography

Pulsed digital holography, which is a new detection method, is a combination of the pulsed laser and digital holography.ultra short pulsed digital holography become a very powerful tool in the regime of recording and reconstructing ultra fast dynamic process, which has unique advantage in timed and spatial detecting of high resolution.It has wide application in 3D measurement, superresolution, ultrafast phenomenon detection. The ultrafast phenomenon, such as 3D temporal and spatial distribution of THz filed, femtosecond laser induced air plasma, can be detected by this method.Subject comes from the national natural science foundation of special instrument. In this paper, based on pulsed digital holography, we have done many original research:1: Pulse digital holographic detection system in the femtosecond laser pulse shape research. Between autocorrelation and cross-correlation method is analyzed on the difference of pulse measurement precision, and using the method of autocorrelation of femtosecond laser double pulse detection, this paper puts forward a kind of double-pulse parameter of the autocorrelation of nonlinear fitting method. To calculate the pulse width, pulse interval and double pulse strength than the parameters, and with the cross-correlation detection method to do the contrast test, this paper demonstrates that the proposed nonlinear fitting method can effectively reduce the amount of error in multiple pulse detection.2: The study of pulse digital holographic detection system in the step type adjustment of pulse interval collinear transmission pulse sequence. Design based on thin film splitting mirror and the structure of the combined delay line pulse interval can regulate the linkage of the beam in a wide range of solution, reduces the light path adjustment link, achieve the purpose of the instrumented building work.3: The research of pulse digital holographic detection system of double wollaston prisms produces four directions ultrafast laser pulses. A design is put forward based on double wollaston prisms. According to the content of the proposed solutions, built a set of double wollaston prism beam system, and record the associated hologram. In subsequent hologram processing, spectrum distribution also met the super fast holographic recording.The significance of the design is to simplify the overall structure of the reference light, and in other areas such as laser processing has extensive application value.The innovative works obtained are as follows:1: This paper presents a nonlinear fitting method to measuring the parameters of the double femtosecond laser pulses.The part of work is published in the Acta Photonica Sinica.2: To have a large adjustable pulse interval of the sub-pulses, a new implement is designed. A patent “Multiple sub-pulses generation with pulse interval can be adjusted in a wide span”(No.201410334680.0) have being applied.3:Reference sub-pulse generation based on Wollaston Prism with temporal and spatial distribution adjustable ability is proposed. A patent “Space angles of transmission beam method and splitting device”(No.201410334678.3) have being applied.