New semiconductor laser designs and the exploratory investigation of the terahertz frequency range

Belyanin, Aleksei A.; Deppe, D.G.; Kocharovskii, Vit V.; Kocharovskii, Vlad V.; Pestov, Dmitrii S.; Sculli, Marlan O.

doi:10.3367/ufnr.0173.200309k.1015

Cited by 13 publications

(1 citation statement)

References 57 publications

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“…1,2 In such a device an injection current pumping is possible, quantum wells play simultaneously a part of active and nonlinear medium, and large intensity of intracavity fields guarantees high efficiency of difference-frequency generation even at room temperature. The long-wavelength radiation is produced in the process of differencefrequency generation via nonlinear mixing of two optical fields, continuous wave and pulsed (or both pulsed), due to the resonant intersubband quantum coherence in quantum wells as well as due to the non-resonant secondorder bulk nonlinearity of a heterostructure.…”

Section: Introductionmentioning

confidence: 99%

Terahertz generation via intracavity mixing in mode-locked dual-wavelength lasers

Андрианов¹,

Kukushkin²,

Kocharovsky³

et al. 2007

SPIE Proceedings

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Section: Introductionmentioning

confidence: 99%

Terahertz generation via intracavity mixing in mode-locked dual-wavelength lasers

Андрианов¹,

Kukushkin²,

Kocharovsky³

et al. 2007

SPIE Proceedings

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Generation of self-sustained pulsations of radiation in InGaAs/GaAs/InGaP quantum-well lasers

et al. 2007

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We studied the dynamic characteristics of InGaAs/GaAs/InGaP quantum-well lasers generating at two wavelengths of about 1 µm with a spectral separation of 15-40 nm. We observed experimentally regimes of jumplike switching and self-sustained pulsations of radiation. The influence of ballistic transfer of carriers during intraband absorption on the production of positive feedback in the dynamic system is studied theoretically.Key words: quantum-well semiconductor laser, self-sustained pulsation of radiation, intraband absorption, ballistic carrier transfer.Introduction. The most promising method at present for generating terahertz and far-IR radiation is considered to be nonlinear generation of a difference frequency during mixing of two fields of near and middle IR ranges [1,2]. Dual-frequency generation of radiation with wavelengths of about 1 µm and spectral separation 5-40 nm was achieved in GaAs/InGaAs/InGaP heterostructures [3,4]. The active region of the laser structures included three quantum wells (QW) that differed in band gap. One narrow-band QW was located between two broad-band QWs. The wave producing layer was 0.8 µm thick; the diodes, 1 mm long and 100 µm wide.Experimental. Spectral and dynamic characteristics of the emitters were studied using pulsed pumping with a pulse length of 100-300 ns and a repeat frequency of 1-10 kHz. Spectral components of the laser radiation were isolated using a KSVU-23 with bandpass ∆λ < 1 nm. Emitters were separated into two basic groups according to their characteristics. Long-wavelength radiation had the minimum threshold in the first group of emitters. After exceeding the threshold of short-wavelength radiation, self-sustaining pulsations of radiation began to be generated (Fig. 1). In the second group, short-wavelength radiation had the minimum threshold. Generation was switched on using a jump regime. Self-sustaining pulsations of radiation arose at a certain value above the threshold current. If the threshold current was significantly exceeded, all lasers gave random radiation pulsations. The transition from quasi-regular pulsations to random ones may have been related to the multi-mode composition of the radiation from the studied lasers.Calculations. Positive feedback should occur for generation of self-sustaining radiation pulses in the system. This can arise in the laser electrical circuit because of negative differential resistance typical of laser structures with heterogeneous excitation [5]. However, negative differential resistance occurs only in a small current range near the threshold of jump-switched generation whereas the studied lasers generated pulsations at two and three times the current threshold.Positive feedback is known to arise with a saturating absorber in the laser resonator. Effective restoration of the short-wavelength radiation absorber during relaxation pulsations can be achieved during generation in the corresponding QW of long-wavelength radiation [6]. However, such a mechanism is evidently not realized in the studied structures becaus...

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Terahertz Oscillator Based on Nonlinear Frequency Conversion in a Double Vertical Cavity

Morozov

2005

Semiconductors

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New semiconductor laser designs and the exploratory investigation of the terahertz frequency range

Cited by 13 publications

References 57 publications

Terahertz generation via intracavity mixing in mode-locked dual-wavelength lasers

Terahertz generation via intracavity mixing in mode-locked dual-wavelength lasers

Generation of self-sustained pulsations of radiation in InGaAs/GaAs/InGaP quantum-well lasers

Terahertz Oscillator Based on Nonlinear Frequency Conversion in a Double Vertical Cavity

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