What is short time scale physics

Short time scale physics deals with physical and technical effects and phenomena that occur in short time periods. These time spans can be in the range of a few hundredths of a second or in the range of femtoseconds, (10^-15 s), or even attoseconds (10^-18 s).

Short time scale physics includes fast-running processes, such as currents, up to the supersonic range, but also fast-running hard pressure waves, so-called shock waves, e.g. with applications in detonation research and in medicine (kidney stone smashers). Furthermore, processes in motor vehicle engines, where fast chemical reactions and the combustion processes taking place during them are investigated with modern methods like laser methods, in order to further reduce pollutant emissions, are a topic area.

This also includes fast electronic processes in solids or semiconductors, such as those that occur when switching power and in modern integrated circuits.

In addition, there are processes and procedures that are not possible at all in continuous operation, since the physical quantities that would occur in the process, such as energy, current strength, temperature, pressure and electric field strength, would assume extremely high uncontrollable values. These can therefore only be carried out impulsively during short periods of time. This enables peak performances in the Mega- to Terawatt range as well as pressures in the Meg-a and Gigabar range to be achieved. Such states can be generated, for example, by irradiating matter with ultra-short intensive laser pulses. For example, ultra-short X-ray pulses can be generated, which in turn can be used to investigate processes or materials. The generation of radiation using various methods (e.g. laser, particle beams, discharges, microdischarges) in a wide spectral range - from the visible to the ultraviolet to the EUV ("soft x-ray") range - and their applications are therefore also integrated.

Series of high-speed images showing the impact of a shock wave on a cone:
(Recording: 370000 Images/s; ISL; approx. 16 MB)

Another field of short time scale physics includes electric discharge phenomena. In contrast to plasma physics, technical applications such as switching high currents and voltages in power engineering are considered. High power pulse technology ("pulsed power" technology), the provision of high electrical power in short times and their applications is, besides laser systems and their applications, another core topic of short time scale physics. Examples are the modules for the generation of pulsed high voltage in gas lasers as well as switching systems based on gas discharges or semiconductor

List of topics: 

Short time dynamics	Short time diagnostics	High Power-/Impuls systems
- High pressure physics - gas dynamics / combustion - Detonic	- electronic procedures - optical procedures - new procedures	- Components for Pulsed-Power Technology - Pulsed Power Systems / Modulators - Applications in Pulsed Power - Measurement Technology in Pulsed Power Systemen - Bioelectrics

Another field of short time scale physics is the interaction of laser radiation with matter and the generation of laser radiation. In addition to classical gas lasers (CO₂ lasers, excimer lasers), the modern concepts of solid-state lasers (fiber lasers, disk lasers) are also part of short-term physics, both in continuous wave and pulsed mode. The application of laser radiation for material processing, e.g. for cutting, welding, drilling, hardening, surface modifications, etc., and the physical effects occurring both in macroscopic applications and in micro material processing are also subject areas of short time scale physics.

The various model positions for the interaction of intensive laser radiation with matter, which are already well advanced for many areas of application and which in some cases already allow reliable predictions, must also be taken into account. Ultra-short pulse lasers play a special role in this context due to the predominantly occurring electronic interaction mechanisms and open up an enormous spectrum of innovative applications. On the one hand, they enable outstanding precision in material processing and are indispensable in today's photonic basic research. On the other hand, they place extreme demands on the optical components used and thus constitute an important branch of short time scale physics in the development, characterization and analysis of laser optics of all kinds.

 

Demonstration of the laser radiation resistance of a rugate filter in the application with a Nd:YAG laser at a wavelength of 1.064 nm and a pulse duration of 8 ns. The exposure time of the image was 30 seconds. The intensity of the laser here is so high that dielectric breakthroughs are formed in the air in the form of local plasmas. The mirror was still fully functional after 30 min irradiation time. (Image: LZH)

List of Topics: 

Laser	radiation sources
- Laser systems - Laser beam interactions - Laser applications - Laser components - high-performance laser - Non-linear Processes	- Fast changing plasmas - non-coherent radiation sources - Laser plasma sources - DUV - VUV - EUV - BEUV– ources and their applications - X-ray laser