Gigawatts and beyond solid-state Terahertz generators/oscillators

In summary, according to the Vacuum Electronic High Power Terahertz Sources book, solid-state Terahertz radiation generators/oscillators are better suited for high power applications than vacuum tube radiation generators/oscillators. However, both types of devices have their own advantages and limitations.
  • #1
Rev. Cheeseman
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TL;DR Summary
Highest power Terahertz oscillator made with a solid-state device instead of vacuum electronics device
According to Vacuum Electronic High Power Terahertz Sources book by John H Booske,

"In solid state electronic devices, the electron stream is a conduction (ohmic, collisional) current whereas in vacuum electronic devices (VEDs) the current is a convection (ballistic, collisionless) current. Thus, the electron transport medium—semiconductor versus vacuum—represents the most fundamental difference between solid state and vacuum electronic devices, respectively. Especially for high power devices needing high power electron currents, the vacuum is a “perfect material” [11]. Electrons moving in a vacuum encounter no scattering. Consequently, VEDs are intrinsically superior at handling high power or high power density [3], [10], [12]. Development of VED sources of THz radiation has, therefore, primarily focused on applications calling for either high average power or high average power density, i.e., relatively high power in a compact package and usually with the highest achievable device efficiencies"

Some people said vacuum tubes will produce the highest power output in generating Terahertz radiation, but I'm wondering if it is possible to make a solid-state Terahertz radiation oscillator or generator that can generate higher power and frequency than any high power vacuum tube Terahertz generator/oscillator. In the absolute sense, I think, both vacuum tubes and solid-state devices are actually very tunable that we can set the power and frequency according to our liking given that we have enough cost and so on. Thoughts?
 
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  • #2
Welcome to the PF. :smile:

Interesting question and interesting field. I do know that for some high-power applications in the more modest frequency bands (like high power radars and radio transmitters), vacuum tube electronics is sometimes preferred. The THz band is new to me though. I found this interesting article with a quick Google search...

https://ieeexplore.ieee.org/document/5993476
 
  • #3
berkeman said:
Welcome to the PF. :smile:

Interesting question and interesting field. I do know that for some high-power applications in the more modest frequency bands (like high power radars and radio transmitters), vacuum tube electronics is sometimes preferred. The THz band is new to me though. I found this interesting article with a quick Google search...

https://ieeexplore.ieee.org/document/5993476

Thank you. That's the full article. :wink:

Meanwhile, at the same time, I'm searching for articles that talked about high power (around gigawatt and beyond) solid-state Terahertz generators/oscillators.
 
  • #4
It will come down to your definition, and the costs for any particular wavelength application.

Up to 1 THz the highest power will be generated by a gyrotron, which is a vacuum tube.
https://en.wikipedia.org/wiki/Gyrotron
How far above 1 THz that may hold we do not yet know.

Fundamentally, the temperature of a semiconductor will limit the power available before the “solid-state” semiconductor material is “cooked” and it ceases to operate.

A gas MASER will need a stable chemical with an appropriate transition. Do you preclude that by insisting on a true hard vacuum device?

Do you consider a Ruby LASER to be a “solid-state” device?
https://en.wikipedia.org/wiki/Ruby_laser
 
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  • #5
First, I have to tell you guys I have a limited understanding in engineering but I just started to be interested in these topics. So, if there is anything wrong please correct me.

I have read some articles on gyrotrons and other vacuum electronic devices like klystrons, backward wave oscillators, vircators, and others. These vacuum electronic devices seem very different from the usual vacuum tubes that we used for audio amplification. Are masers considered to be true vacuum tubes? In my opinion, I see them more like vacuum chambers that work much more differently than true vacuum tubes such as triodes, tetrodes, pentodes, etc. I also tend to look at gyrotrons and others that I have mentioned before to be very different from those true vacuum tubes.

Anyway I just found these articles, 0.5 terawatt laser based on a hybrid architecture for high energy diode-pumped lasers delivering sub-500 fs pulses

And...

The design goal for the “High repetition-rate Advanced Petawatt Laser System” (HAPLS) calls for peak powers greater than one petawatt (1015 watts, or 1,000,000,000,000,000 watts) at a repetition rate of 10 hertz, with each pulse lasting less than 30 femtoseconds, or 0.00000000000003 seconds. HAPLS combines sophisticated semiconductor diode laser technology with advanced optics, integrated control systems and techniques for managing the production of ultra-short pulses of light delivered at a repetition rate that is well-suited for the various applications planned for study at the facility.

Looks like with enough cost and everything, we can make very high power Terahertz (or any radiation) generators/oscillators with both vacuum tubes and solid-state devices. What do you think?
 
  • #6
wonderingchicken said:
Looks like with enough cost and everything, we can make very high power Terahertz (or any radiation) generators/oscillators with both vacuum tubes and solid-state devices. What do you think?
I do not think there need be a distinction between vacuum and solid-state devices. The source employed will depend on many things. There is no advantage in a restrictive generalisation.

Terahertz pulses are used for close range surface imaging through fabrics. Increased security explains why it is receiving more attention.

1 Petawatt, for 30 femtoseconds, at 10 Hz rate does sound good.
But the average power would be 1 Pwatt * 30 fsec * 10 Hz = 300 watt.

You should be able to find the following books...
Title: Field Guide to Terahertz Sources, Detectors, and Optics. (SPIE Field Guides FG28)
Publisher: SPIE Press Year 2012, Author(s): Créidhe O'Sullivan, J. Anthony Murphy.

Latest...
Title: Emerging Trends in Terahertz Solid-State Physics and Devices: Sources, Detectors, Advanced Materials, and Light-matter Interactions.
Editors: Arindam Biswas, Amit Banerjee, Aritra Acharyya, Hiroshi Inokawa, Jintendra Nath Roy
Publisher: Springer, Year: 2020, ISBN: 9811532346, 9789811532344

20 years older...
Title: Terahertz Sources and Systems. Edited by R. E. Miles, P. Harrison and D. Lippens.
Publisher: Springer, Year: 2001, ISBN 978-0-7923-7097-0
 
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  • #7
You need to define what you mean by "THz".
BWOs and other conventional electronics work well up to a few hundred GHz.
A the other end you have various FIR lasers etc which tend to work down to perhaps 2-3 THz,

The "problem" is the range from maybe 750 GHz to say 2 THz. This is -AFAIK- the range where there is a need to develop new sources and detectors.

You also need consider what "high power" mean for radiation that can be relatively easily focused. In many applications "high power" would mean say 1-2 watts; I don't know of any THz applications that require hundreds of Watts.
 
  • #8
f95toli said:
You need to define what you mean by "THz".
BWOs and other conventional electronics work well up to a few hundred GHz.
A the other end you have various FIR lasers etc which tend to work down to perhaps 2-3 THz,

The "problem" is the range from maybe 750 GHz to say 2 THz. This is -AFAIK- the range where there is a need to develop new sources and detectors.

You also need consider what "high power" mean for radiation that can be relatively easily focused. In many applications "high power" would mean say 1-2 watts; I don't know of any THz applications that require hundreds of Watts.

I should rephrase it as from 1 Terahertz, which is already in the infrared region, and beyond.

According to some articles I've found online, not sure if I understand them correctly, the maximum frequencies that gyrotrons can generate are around 1 THz to 1.7 THz with highest power output around several gigawatt.

This article https://www.osti.gov/biblio/6233581...-simulation-technology-laboratory-guide-users talked about a gamma ray generator (more like a particle accelerator) with 15 terawatt power output and very high energy at 20 megavolt. It have electrodes such as a cathode and an anode in a vacuum chamber like a typical vacuum tube, but is it a true vacuum tube or not I'm not sure.
 

Related to Gigawatts and beyond solid-state Terahertz generators/oscillators

1. What is a gigawatt and how is it related to solid-state Terahertz generators/oscillators?

A gigawatt is a unit of power equal to one billion watts. It is commonly used to measure the output power of high-energy devices such as solid-state Terahertz generators/oscillators. These generators/oscillators use gigawatts of power to produce Terahertz radiation, which is in the range of 1 to 10 trillion hertz.

2. How do solid-state Terahertz generators/oscillators work?

Solid-state Terahertz generators/oscillators use high-power lasers or electron beams to excite a material, such as a semiconductor or a gas, to produce Terahertz radiation. This radiation can then be amplified and directed using various techniques to generate gigawatts of power.

3. What are the potential applications of solid-state Terahertz generators/oscillators?

Solid-state Terahertz generators/oscillators have a wide range of potential applications, including medical imaging, security screening, and communication systems. They can also be used in scientific research for studying materials, chemical reactions, and biological processes at the Terahertz frequency range.

4. How do solid-state Terahertz generators/oscillators differ from other types of Terahertz generators/oscillators?

Solid-state Terahertz generators/oscillators differ from other types of Terahertz generators/oscillators in that they use solid-state materials, such as semiconductors, instead of gases or vacuum tubes. This allows for more compact and efficient devices with higher power output.

5. What are the challenges in developing gigawatt-level solid-state Terahertz generators/oscillators?

Developing gigawatt-level solid-state Terahertz generators/oscillators is a complex and challenging task. Some of the main challenges include finding suitable materials that can withstand the high-power levels, designing efficient and reliable power sources, and developing techniques to amplify and direct the Terahertz radiation. Additionally, the cost of these devices can also be a barrier to their widespread use.

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