Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices
The detailed theoretical study of high-frequency signal gain, when a probe microwave signal is comparable to the AC pump electric field in a semiconductor superlattice, is presented. We identified conditions under which a doped superlattice biased by both DC and AC fields can generate or amplify hig...
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MDPI AG
2023-07-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/13/1993 |
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| author | Vladislovas Čižas Natalia Alexeeva Kirill N. Alekseev Gintaras Valušis |
| author_facet | Vladislovas Čižas Natalia Alexeeva Kirill N. Alekseev Gintaras Valušis |
| author_sort | Vladislovas Čižas |
| collection | DOAJ |
| description | The detailed theoretical study of high-frequency signal gain, when a probe microwave signal is comparable to the AC pump electric field in a semiconductor superlattice, is presented. We identified conditions under which a doped superlattice biased by both DC and AC fields can generate or amplify high-frequency radiation composed of harmonics, half-harmonics, and fractional harmonics. Physical mechanisms behind the effects are discussed. It is revealed that in a general case, the amplification mechanism in superlattices is determined by the coexistence of both the phase-independent Bloch and phase-dependent parametric gain mechanisms. The interplay and contribution of these gain mechanisms can be adjusted by the sweeping AC pump strength and leveraging a proper phase between the pump and strong probe electric fields. Notably, a transition from the Bloch gain to the parametric gain, often naturally occurring as the amplitude of the amplified signal field grows, can facilitate an effective method of fractional harmonic generation in DC–AC-driven superlattices. The study also uncovers that the pure parametric generation of the fractional harmonics can be initiated via their ignition by switching the DC pump electric field. The findings open a promising avenue for the advancement of new miniature GHz–THz frequency generators, amplifiers, and dividers operating at room temperature. |
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| id | doaj.art-7592517e1f4b451fa78aacf0d5f25da6 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-11T01:33:18Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-7592517e1f4b451fa78aacf0d5f25da62023-11-18T17:12:23ZengMDPI AGNanomaterials2079-49912023-07-011313199310.3390/nano13131993Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped SuperlatticesVladislovas Čižas0Natalia Alexeeva1Kirill N. Alekseev2Gintaras Valušis3Department of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, LithuaniaDepartment of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, LithuaniaDepartment of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, LithuaniaDepartment of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, LithuaniaThe detailed theoretical study of high-frequency signal gain, when a probe microwave signal is comparable to the AC pump electric field in a semiconductor superlattice, is presented. We identified conditions under which a doped superlattice biased by both DC and AC fields can generate or amplify high-frequency radiation composed of harmonics, half-harmonics, and fractional harmonics. Physical mechanisms behind the effects are discussed. It is revealed that in a general case, the amplification mechanism in superlattices is determined by the coexistence of both the phase-independent Bloch and phase-dependent parametric gain mechanisms. The interplay and contribution of these gain mechanisms can be adjusted by the sweeping AC pump strength and leveraging a proper phase between the pump and strong probe electric fields. Notably, a transition from the Bloch gain to the parametric gain, often naturally occurring as the amplitude of the amplified signal field grows, can facilitate an effective method of fractional harmonic generation in DC–AC-driven superlattices. The study also uncovers that the pure parametric generation of the fractional harmonics can be initiated via their ignition by switching the DC pump electric field. The findings open a promising avenue for the advancement of new miniature GHz–THz frequency generators, amplifiers, and dividers operating at room temperature.https://www.mdpi.com/2079-4991/13/13/1993superlatticeamplificationlarge signalmicrowavesterahertzsub-harmonic |
| spellingShingle | Vladislovas Čižas Natalia Alexeeva Kirill N. Alekseev Gintaras Valušis Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices Nanomaterials superlattice amplification large signal microwaves terahertz sub-harmonic |
| title | Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices |
| title_full | Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices |
| title_fullStr | Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices |
| title_full_unstemmed | Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices |
| title_short | Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices |
| title_sort | coexistence of bloch and parametric mechanisms of high frequency gain in doped superlattices |
| topic | superlattice amplification large signal microwaves terahertz sub-harmonic |
| url | https://www.mdpi.com/2079-4991/13/13/1993 |
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