Characterizing a 474 nm Laser as a Source for Spontaneous Parametric Down Conversion
Document Type
Oral Presentation
Campus where you would like to present
SURC 140
Start Date
16-5-2013
End Date
16-5-2013
Abstract
There is an important class of experiments that characterize the properties of quantum mechanical systems using correlated photons, and a typical source for correlated photons is the process of Spontaneous Parametric Down Conversion (SPDC). SPDC is a quantum mechanical process in which a single “pump” photon is converted into two photons that have half the frequency and double the wavelength of the original photon. This process takes place inside a crystal with particular optical properties that allow for SPDC, and we used a uniaxial Beta Barium Borate crystal. A single photon counting module (SPCM) was used as a detector for the photons. Our goal was to characterize a 474 nanometer (nm) Diode Pumped Solid State (DPSS) laser as a possible source for SPDC correlated photons. Measurements of the DPSS laser radiation showed that it emitted photons with a wavelength of both 474 nm and 948 nm, which was expected. The SPDC photons produced by our apparatus would also have a wavelength of 948 nm, so we tested whether the down converted photons could be detected without the 948 nm signal from the DPSS laser overwhelming the SPCM. Software for determining the parameters of SPDC in a given system is available from the National Institute of Standards and Technology, and we used it to determine where we could expect to see SPDC photons. Initial measurements suggest that the system can produce SPDC photons, and we will continue to characterize the apparatus.
Recommended Citation
Balmer, Joshua and Howard, Lex, "Characterizing a 474 nm Laser as a Source for Spontaneous Parametric Down Conversion" (2013). Symposium Of University Research and Creative Expression (SOURCE). 9.
https://digitalcommons.cwu.edu/source/2013/oralpresentations/9
Additional Mentoring Department
Physics
Characterizing a 474 nm Laser as a Source for Spontaneous Parametric Down Conversion
SURC 140
There is an important class of experiments that characterize the properties of quantum mechanical systems using correlated photons, and a typical source for correlated photons is the process of Spontaneous Parametric Down Conversion (SPDC). SPDC is a quantum mechanical process in which a single “pump” photon is converted into two photons that have half the frequency and double the wavelength of the original photon. This process takes place inside a crystal with particular optical properties that allow for SPDC, and we used a uniaxial Beta Barium Borate crystal. A single photon counting module (SPCM) was used as a detector for the photons. Our goal was to characterize a 474 nanometer (nm) Diode Pumped Solid State (DPSS) laser as a possible source for SPDC correlated photons. Measurements of the DPSS laser radiation showed that it emitted photons with a wavelength of both 474 nm and 948 nm, which was expected. The SPDC photons produced by our apparatus would also have a wavelength of 948 nm, so we tested whether the down converted photons could be detected without the 948 nm signal from the DPSS laser overwhelming the SPCM. Software for determining the parameters of SPDC in a given system is available from the National Institute of Standards and Technology, and we used it to determine where we could expect to see SPDC photons. Initial measurements suggest that the system can produce SPDC photons, and we will continue to characterize the apparatus.
Faculty Mentor(s)
Michael Braunstein