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http://global.ofweek.com/news/Raman-scattering-key-to-next-gen-laser-optical-comms-13900
The improvements in the performance of powerful lasers, optical fibres and peripheral technology have provided a sizable contribution to the proliferation of global telecommunications based on the transmission of 10GHz pulses of light. Particularly, the three most important properties of lasers for telecommunications are high power, single frequency and ultra-short pulse width.
Innovations pertaining to this technology can be found in the research being conducted by Professor Masayuki Katsuragawa, at the department of applied physics and chemistry, UEC.
"My research is focused on the manipulation of light-matter interaction for producing ultra-short pulses of laser light," stated Katsuragawa. "Our recent experiments on adiabatic stimulated Raman scattering in parahydrogen show potential for the realisation of laser light sources producing pulses at terahertz repetition-rate frequencies. These ultra-short pulses offer a new 'axis' in the evolution of laser based optical science."
Here, the 'axis' refers to ultrahigh-repetition-rate trains of monocycle pulses with precise control of the phase of the laser light pulses. Recently, Katsuragawa and his colleagues have reported on the realisation of ultrashort pulse trains of 1.8fs in duration and repetition frequency of 125THz by stimulated Raman scattering (SRSs) produced in parahydrogen. "The critical point in these experiments was driving Raman coherence adiabatically, that is, without dissipation," said Katsuragawa. "We achieved this by developing an injection-locked laser capable of emitting arbitrary pairs of two frequencies to irradiate the hydrogen gas, in order to control two photon detuning from the Raman resonance."
Recently, the UEC team has produced higher order series of stimulated Raman scattering using two driving lasers by the introduction of a second harmonic in one of the lasers. The resulting emission referred to as a 'Raman comb,' covered an octave spectrum range from the infrared to the ultraviolet.
"I am confident that our research has laid the foundations for the development of practical systems for the generation of trains of monocycle pulses with total control of the phase," noted Katsuragawa.
Innovations pertaining to this technology can be found in the research being conducted by Professor Masayuki Katsuragawa, at the department of applied physics and chemistry, UEC.
"My research is focused on the manipulation of light-matter interaction for producing ultra-short pulses of laser light," stated Katsuragawa. "Our recent experiments on adiabatic stimulated Raman scattering in parahydrogen show potential for the realisation of laser light sources producing pulses at terahertz repetition-rate frequencies. These ultra-short pulses offer a new 'axis' in the evolution of laser based optical science."
Here, the 'axis' refers to ultrahigh-repetition-rate trains of monocycle pulses with precise control of the phase of the laser light pulses. Recently, Katsuragawa and his colleagues have reported on the realisation of ultrashort pulse trains of 1.8fs in duration and repetition frequency of 125THz by stimulated Raman scattering (SRSs) produced in parahydrogen. "The critical point in these experiments was driving Raman coherence adiabatically, that is, without dissipation," said Katsuragawa. "We achieved this by developing an injection-locked laser capable of emitting arbitrary pairs of two frequencies to irradiate the hydrogen gas, in order to control two photon detuning from the Raman resonance."
Recently, the UEC team has produced higher order series of stimulated Raman scattering using two driving lasers by the introduction of a second harmonic in one of the lasers. The resulting emission referred to as a 'Raman comb,' covered an octave spectrum range from the infrared to the ultraviolet.
"I am confident that our research has laid the foundations for the development of practical systems for the generation of trains of monocycle pulses with total control of the phase," noted Katsuragawa.
"Raman comb" generated by modulating single-frequency laser radiation with coherent molecular oscillations.
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