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Frequency-resolved optical gating measurement of ultrashort pulses by using single nanowire

View Article: PubMed Central - PubMed

ABSTRACT

The use of ultrashort pulses for fundamental studies and applications has been increasing rapidly in the past decades. Along with the development of ultrashort lasers, exploring new pulse diagnositic approaches with higher signal-to-noise ratio have attracted great scientific and technological interests. In this work, we demonstrate a simple technique of ultrashort pulses characterization with a single semiconductor nanowire. By performing a frequency-resolved optical gating method with a ZnO nanowire coupled to tapered optical microfibers, the phase and amplitude of a pulse series are extracted. The generated signals from the transverse frequency conversion process can be spatially distinguished from the input, so the signal-to-noise ratio is improved and permits lower energy pulses to be identified. Besides, since the nanometer scale of the nonlinear medium provides relaxed phase-matching constraints, a measurement of 300-nm-wide supercontinuum pulses is achieved. This system is highly compatible with standard optical fiber systems, and shows a great potential for applications such as on-chip optical communication.

No MeSH data available.


Experiment setup of FROG.WP: wave plate; L1 and L2: focal lens; M1-M3: total-reflection mirror. Inset: Bright-field optical microscope image of a suspended ZnO NW with 810 nm input from both ends.
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f2: Experiment setup of FROG.WP: wave plate; L1 and L2: focal lens; M1-M3: total-reflection mirror. Inset: Bright-field optical microscope image of a suspended ZnO NW with 810 nm input from both ends.

Mentions: The schematic diagram of the measurement setup is illustrated in Fig. 2. A Ti:Sapphire mode-locked laser with central wavelength at 810 nm (80 MHz, ~70 fs, Spectra-Physics) was used here. After going through an isolator and a pinhole, the laser beam was split into two halves by a wave plate and a polarization beam splitter (PBS). The input power of the 810 nm pulsed light was ~10 mW for each arm and the light transfer efficiency was measured to be ~60% for single taper-NW coupling. One beam was used as target pulse, and the other beam as gate pulse was introduced into a retro-reflector, by which the length of optical path can be tuned directly. Two beams were individually coupled into two single-mode fibers (112 cm long each) whose ends were tapered to microfibers. Both tapered microfibers were suspended above a MgF2 microchannel with ~200 μm in seperation. A 245-μm-long, 310-nm-diameter ZnO NW was coupled with them via micro-manipulation under optical microscope131417. The angle and position of both tapers can be carefully adjusted to maintain an optimal input coupling efficiency. The surface emitted signal from the NW was collected by a objective lens, and then filtered and directed into a CCD (DS Ri1, Nikon); part of the signal was reflected by a neutral beam-splitter (45/55) into a spectrometer (QE65 pro, Ocean Optics).


Frequency-resolved optical gating measurement of ultrashort pulses by using single nanowire
Experiment setup of FROG.WP: wave plate; L1 and L2: focal lens; M1-M3: total-reflection mirror. Inset: Bright-field optical microscope image of a suspended ZnO NW with 810 nm input from both ends.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016840&req=5

f2: Experiment setup of FROG.WP: wave plate; L1 and L2: focal lens; M1-M3: total-reflection mirror. Inset: Bright-field optical microscope image of a suspended ZnO NW with 810 nm input from both ends.
Mentions: The schematic diagram of the measurement setup is illustrated in Fig. 2. A Ti:Sapphire mode-locked laser with central wavelength at 810 nm (80 MHz, ~70 fs, Spectra-Physics) was used here. After going through an isolator and a pinhole, the laser beam was split into two halves by a wave plate and a polarization beam splitter (PBS). The input power of the 810 nm pulsed light was ~10 mW for each arm and the light transfer efficiency was measured to be ~60% for single taper-NW coupling. One beam was used as target pulse, and the other beam as gate pulse was introduced into a retro-reflector, by which the length of optical path can be tuned directly. Two beams were individually coupled into two single-mode fibers (112 cm long each) whose ends were tapered to microfibers. Both tapered microfibers were suspended above a MgF2 microchannel with ~200 μm in seperation. A 245-μm-long, 310-nm-diameter ZnO NW was coupled with them via micro-manipulation under optical microscope131417. The angle and position of both tapers can be carefully adjusted to maintain an optimal input coupling efficiency. The surface emitted signal from the NW was collected by a objective lens, and then filtered and directed into a CCD (DS Ri1, Nikon); part of the signal was reflected by a neutral beam-splitter (45/55) into a spectrometer (QE65 pro, Ocean Optics).

View Article: PubMed Central - PubMed

ABSTRACT

The use of ultrashort pulses for fundamental studies and applications has been increasing rapidly in the past decades. Along with the development of ultrashort lasers, exploring new pulse diagnositic approaches with higher signal-to-noise ratio have attracted great scientific and technological interests. In this work, we demonstrate a simple technique of ultrashort pulses characterization with a single semiconductor nanowire. By performing a frequency-resolved optical gating method with a ZnO nanowire coupled to tapered optical microfibers, the phase and amplitude of a pulse series are extracted. The generated signals from the transverse frequency conversion process can be spatially distinguished from the input, so the signal-to-noise ratio is improved and permits lower energy pulses to be identified. Besides, since the nanometer scale of the nonlinear medium provides relaxed phase-matching constraints, a measurement of 300-nm-wide supercontinuum pulses is achieved. This system is highly compatible with standard optical fiber systems, and shows a great potential for applications such as on-chip optical communication.

No MeSH data available.