Spectral analysis of a phase locked laser at 891 GHz, an application of Josephson junctions in the far infrared
نویسندگان
چکیده
2014 We have used a Josephson junction to investigate the spectral purity of an HCN laser which is used in an infrared frequency synthesis chain. To obtain a narrower linewidth from the laser it has been phase locked to a multiplied microwave reference chain. A calculated value for this linewidth was based upon the measured noise spectrum of the microwave source and a theory due to Middleton. One can take advantage of the unique properties of the Josephson junction as a frequency multiplier and mixer for use in measuring this linewidth. The Josephson junction is driven by an X-band signal which is derived from a specially designed cavity stabilized klystron system of high spectral purity. The 92nd harmonic of the X-band signal is generated in the Josephson junction. In addition, the Josephson junction acts as a mixer of the harmonic signals and the 891 GHz output of the HCN laser. The 92nd harmonic beat signal is taken from the Josephson junction, amplified, and sent to a spectrum analyzer for frequency domain analysis. Details of the experiment, results, and relation to predicted linewidths are presented. REVUE DE PHYSIQUE APPLIQUÉE TOME 9, JANVIER 1974, PAGE
منابع مشابه
Properties of Josephson Point-contact Far-infrared Detectors
The far-infrared (FIR) properties of niobium cat-whisker point contacts were studied using radiation from an optically pumped FIR laser. The reproducible behaviour of junctions with excellent high-frequency performance allowed a measurement of the FIR frequency dependence of the strength of the a.c. Josephson effect. The shape of the laser-induced steps was used to measure the effective noise t...
متن کاملLow Frequency Noise Optically Pumped Fir Laser with Frequency Stabilized Pump
A new method of frequency stabilization of the pumping laser of an optically pumped far infrared laser (OPFIRL) has been developed. With the frequency of the pump stabilized in this way the phase noise of the OPFIRL is minimized and the laser can remain phase locked to an Hydrogen maser for several hours. A measurement of the spectral density of phase noise of the generated submillimetric radia...
متن کاملJosephson Current For a Graphene Nanoribbon Using a Lattice Model
A tight binding approach based on the Bogoliubov-de Gennes approach has been used to calculate the DC Josephson current for a lattice model for S-GNR-S junctions , for short junctions with respect to superconducting coherence length. We calculate the phase, length, width and chemical potential dependence at the Josephson junction and discuss the similarities and differences with regard to the t...
متن کاملSingle axial-mode selection in a far-infrared p-Ge laser
Single axial-mode operation of the pulsed far-infrared p-Ge laser with an intracavity Fabry–Perot type frequency selector has been observed by means of Fourier-transform spectroscopy. A spectral resolution better than 1 GHz has been achieved on an ordinary continuous-scan spectrometer using the event-locked technique for pulsed emission sources. A laser active-cavity finesse of at least unity h...
متن کاملHeterodyne laser radiation detection at 891 GHz using josephson point contacts
2014 Experiments were carried out to investigate the performance of a heterodyne detector at 891 GHz using a cw hydrogen cyanide laser as the local oscillator and Nb-Nb point contact Josephson junctions as mixing devices. Using a second off-tuned HCN laser as the signal, intermediate frequencies (IF’s) up to a few MHz could be studied. Both pre-set and adjustable types of junction were used, an...
متن کامل