Selective volumetric modification of transparent dielectric media by femtosecond laser radiation

control of the optical properties of nanoparticles by laser fields

در این پایان نامه، درهمتنیدگی بین یک سیستم نقطه کوانتومی دوگانه(مولکول نقطه کوانتومی) و میدان مورد مطالعه قرار گرفته است. از آنتروپی ون نیومن به عنوان ابزاری برای بررسی درهمتنیدگی بین اتم و میدان استفاده شده و تاثیر پارامترهای مختلف، نظیر تونل زنی(که توسط تغییر ولتاژ ایجاد می شود)، شدت میدان و نسبت دو گسیل خودبخودی بر رفتار درجه درهمتنیدگی سیستم بررسی شده اشت.با تغییر هر یک از این پارامترها، در...

Generation and Amplification of Tunable Multicolored Femtosecond Laser Pulses by Using Cascaded Four-Wave Mixing in Transparent Bulk Media

We have reviewed the generation and amplification of wavelength-tunable multicolored femtosecond laser pulses using cascaded four-wave mixing (CFWM) in transparent bulk media, mainly concentrating on our recent work. Theoretical analysis and calculations based on the phase-matching condition could explain well the process semi-quantitatively. The experimental studies showed: (1) as many as fift...

Free-electron-laser radiation induced by a periodic dielectric medium.

NUV and NIR Femtosecond Laser Modification of PMMA

Substantial refractive index changes in clinical grade poly(methyl methacrylate) (PMMA) with both femtosecond NIR (800 nm) and NUV (387 nm) laser pulses are demonstrated, enabling volume gratings and waveguides in bulk PMMA. In the NIR, temporal pulse duration is shown to be critical, with modification efficiency increasing rapidly as pulse duration decreases below 200 fs. On the other hand, in...

Structural Modification of Amorphous Fused Silica under Femtosecond Laser Irradiation

Non-linear absorption of femtosecond laser pulses enables the induction of structural changes in the interior of bulk transparent materials without affecting their surface. This property can be exploited for the transmission welding of transparent dielectrics, three dimensional optical data storages and waveguides. In the present study, femtosecond laser pulses were tightly focused within the i...