<p>THz radiation has been significant field of research due to its non-hazardous nature during interaction with living and nonliving matter. Here, we propose to generate THz field by interaction of laser-beat wave with non-uniform collisional plasmas. Required momentum conservation for THz emission is made feasible by the introduced non-uniformity in the form of rippled density plasmas <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12596_2025_2489_Article_IEq1.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="97" /> </InlineMediaObject> <EquationSource Format="TEX">$\left( {n_{0} + n_{\beta } e^{i\beta z} } \right)$</EquationSource> <EquationSource Format="MATHML"><math> <mfenced close=")" open="("> <mrow> <msub> <mi>n</mi> <mn>0</mn> </msub> <mo>+</mo> <msub> <mi>n</mi> <mi>β</mi> </msub> <msup> <mi>e</mi> <mrow> <mi>i</mi> <mi>β</mi> <mi>z</mi> </mrow> </msup> </mrow> </mfenced> </math></EquationSource> </InlineEquation>. Frequency <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12596_2025_2489_Article_IEq2.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="192" /> </InlineMediaObject> <EquationSource Format="TEX">$\omega = \omega_{01} \left( {1 + \alpha \omega_{01} \left( {t - \frac{z}{c}} \right)} \right)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ω</mi> <mo>=</mo> <msub> <mi>ω</mi> <mn>01</mn> </msub> <mfenced close=")" open="("> <mrow> <mn>1</mn> <mo>+</mo> <mi>α</mi> <msub> <mi>ω</mi> <mn>01</mn> </msub> <mfenced close=")" open="("> <mrow> <mi>t</mi> <mo>-</mo> <mfrac> <mi>z</mi> <mi>c</mi> </mfrac> </mrow> </mfenced> </mrow> </mfenced> </mrow> </math></EquationSource> </InlineEquation> varying laser pulses are used to generate the required nonlinear current for THz field generation. Varying frequency lasers reduce the effect of collisions on THz field generation. Threefold enhancement is observed in the efficiency of the present mechanism with increasing values of the chirp parameter.</p>

Resonantly driven terahertz field emission in collisional plasmas: effect of chirped laser pulse

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发表日期：

2025年2月17日

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R. Kumar,
S. Divya,
S. Singh,
A. P. Singh,
K. Gopal

摘要

THz radiation has been significant field of research due to its non-hazardous nature during interaction with living and nonliving matter. Here, we propose to generate THz field by interaction of laser-beat wave with non-uniform collisional plasmas. Required momentum conservation for THz emission is made feasible by the introduced non-uniformity in the form of rippled density plasmas $\left( {n_{0} + n_{\beta } e^{i\beta z} } \right)$ $(n_{0} + n_{β} e^{i β z})$ . Frequency $\omega = \omega_{01} \left( {1 + \alpha \omega_{01} \left( {t - \frac{z}{c}} \right)} \right)$ $ω = ω_{01} (1 + α ω_{01} (t - \frac{z}{c}))$ varying laser pulses are used to generate the required nonlinear current for THz field generation. Varying frequency lasers reduce the effect of collisions on THz field generation. Threefold enhancement is observed in the efficiency of the present mechanism with increasing values of the chirp parameter.