Northwestern University's McCormick School of Engineering develops Portable Terahertz Oscillator

“Using a room-temperature mid-infrared Laser to generate Terahertz Light bypasses the temperature barrier, and all we need to do is to make the output power high enough for practical applications. Most applications require a minimum of microwatt power levels, but, of course, the higher the better”

Dr. Manijeh Razeghi lead Researcher at Northwestern University's McCormick School of Engineering and Applied Science Faculty of Electrical Engineering and Computer Science commenting on their developement of a Room Temperature Compact Terahertz Generator

Dr. Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science at Northwestern University's McCormick School of Engineering and Applied Science has achieved a dream of Telecoms Engineers everywhere. Their Team has developed a compact, room-temperature Terahertz Oscillator source with an output power of 215 microwatts as stated in the article “Team develops compact, high-power terahertz source at room temperature”, published October 09, 2013, Phys.org.

In physics, Terahertz Radiation, also called submillimeter Radiation, consists of electromagnetic waves at frequencies from 0.3 to 3 Terahertz (THz). The term applies to electromagnetic Radiation with frequencies between the high-frequency edge of the millimeter wave band, 300 gigahertz (3×1011 Hz), and the low frequency edge of the far-infrared light band, 3000 GHz (3×1012 Hz). Corresponding wavelengths of Radiation in this band range from 1 mm to 0.1 mm (or 100 μm)It goes by several names; Terahertz waves. Terahertz light, T-rays, T-waves, T-light, T-lux, or THz.

Terahertz Radiation is sometimes known as the submillimeter band, and its Radiation as submillimeter waves, especially in astronomy. Terahertz Radiation occupies a middle ground between microwaves and infrared light waves, and technology for generating and manipulating it is in its infancy, and is a subject of active research.

It represents the region in the electromagnetic spectrum that the frequency of electromagnetic Radiation becomes too high to be measured by directly counting cycles using electronic counters, and must be measured by the proxy properties of wavelength and energy. Similarly, generation and modulation of coherent electromagnetic signals ceases to be possible by the conventional electronic devices used to generate radio waves and microwaves, and requires new devices and techniques.

Their design for the Terahertz Oscillator findings were published originally published on Monday July 1^st 2013 in the Journal Applied Physics Letters and was also presented at the SPIE (Society of Photographic Instrumentation Engineers) Optics + Photonics conference in August in San Diego. Dr. Manijeh Razeghi presented her group's research on Monday October 7^th 2013 at the International Conference and Exhibition on Lasers, Optics & Photonics in San Antonio. They also did another demonstration on Thursday 10^th October 2013 at the European Cooperation in Science and Technology Conference in Sheffield, England. 

Effectively they've developed an Oscillator that can produce Light that operates at room temperature and doesn't need exotic cooling. There’s also a UWI Connection. The Faculty of Pure and Applied Sciences, which was recently renamed the Faculty of Science and Technology with a focus on Optics.

This was thanks to Lead research and Lecturer in the Department of Physics at UWI Mona, Dr. Kert Edward securing a grant from the SPIE for Optics Research as explained in my blog article entitled “UWI's Faculty of Pure and Applied Sciences is now Science and Technology as SPIE funds Optics Research - Welcome to the Punch at a multi-billion dollar Optics Revolution”. So UWI’s already go a foot in the Optics Research door, as the potential of this and many other discoveries is enormous!

Their Terahertz Oscillator has a range of 1 THz to 4.6 THz and is the size of a standard Laser Diode.  They did this in a manner similar to making a higher op amp Amplifier by cascading in series. The Team took 2 different QCL (quantum cascade Lasers), one operating at a wavelength of 9.3 microns and the other at 10.4 microns and stuffed them into a single Laser. Their output was then mixed in a non linear fashion, meaning that it mixer doesn’t amplify all of the QCL Lasers output equally over a specified range, effectively acting like a single Laser.

Terahertz Oscillator Significance – FLORA shines a Light on Telecom Provider Backhaul

The reason that this is a significant development is that for some time Researchers have been trying to develop an Oscillator for Sub-millimeter Waves will eventually advance the development for an oscillator for Visible Light. Light Waves can be produced via combustion, excitation of electrons in metal carrying a current or heat or any phenomenon involving the excitation of electrons from the outer shells orbits to fall to inner orbital’s, releasing a quantum of Radiation in the visible spectra.

But an Oscillator for Terahertz Radiation is special. With such a device, it would be possible to eventually produce Light in the same way we currently artificially produce Radio Waves using an Oscillator or Microwaves using a klystron or Magnetron. This means we can modulate the waves and use it to transmit Data. Currently to do that, we merely turn the Light source on an off rapidly, effectively Morse Code in Fiber Optic Data Transmission Systems.

And albeit these Fiber Optic Data Transmission Systems are fast and can carry far more Bandwidth of multiplexed Data, the limitation of mechanical switching is fast approaching as it relates to how fast you can switch IR (Infrared lasers) on and off to produce the pulses to transmit Data.

It’ll then be possible to use standards form of modulation typically used on Radio Waves such as FM (Frequency Modulation), AM (Amplitude Modulation) and even QAM (Quadrature Amplitude Modulation) to transmit Data. This would mean not only more Data being transmitted more cost effectively with the modulated Light pulses, but also deeper layers of compression of  Data, as not only can you use on an off pulses, but the very Light pulses themselves carry modulate Data, which is great for Data encryption as well.

FLORA – High Bandwidth Backhaul without Fiber Optic and Spectrum Licenses

It also heralds the coming of FLORA (Fiberless Optical Receiver Array) Transmitters based on such Terahertz Oscillator Lasers as if they’re now stable at room temperature and portable, they can then be mounted in place of Microwave Transmitters used in Backhaul for Telecom Networks to interconnect their Cell Towers to their MSC (Mobile Switching Center), allowing Telecom Providers to transmit as much Data as a Fiber Optic Network without the need to lay Fiber Optic Cables.

Even better, it’d reduce the need for Telecom Providers to pay for Spectrum licenses for Microwave Antennas, as Terahertz Oscillator based Backhaul isn’t covered by most Spectrum Management Authorities, which mainly control Radio Waves and Microwaves, not Optical Frequencies….at least for now.

FLORA was one of the technologies that I floated as an alternative for Microwave Backhaul at the SMA (Spectrum Management Authority) had their Stakeholder Consultation Forum on the 700MHz Spectrum Auction at the Jamaica Conference Room in Caucus Room 2 at the Jamaica Conference Center on Tuesday September 10th 2013 as stated in my blog article entitled “Stakeholder Consultation Forum on the 700 MHz Spectrum Auction - How the Spectrum Auction process for Band 17 and Band 13 of the 700 Mhz Band Works”.

It was a part of my original proposal for my design of a 700 MHz 4G LTE (Long Term Evolution) Network proposal Audia_Gypsy_Danger, of which Solar Powered Wi-Fi as described my blog article entitled “Unruly High School Students Making out and having sex in the JUTC Half-Way-Tree Transport Center - How Wi-Fi in Buses can lead to Solar Power, LPG and the SmarterCard Cashless system” and for which I have a Copyright and Patent.

More importantly, it also paves the way for Telecom Systems based on Terahertz Oscillator based lasers that can be used not only for Backhaul but even for communication with Cell Phones, Tablets and Laptops. This is in much the same way Bluetooth and Wi-Fi work, only in the Optical Spectrum and would appear to users as merely ordinary lighting fixtures as explained in my blog article entitled “EPSRC and University of Strathclyde researches FLORA based Li-Fi for developement in the next four years - Selena Gomez’s Come and Get It FLORA Li-Fi for Last Mile Internet to be Downloaded”.

FLORA Based Communications can potentially replace Microwave Transmitters used for other services such as Point-to-Point Private Microwave Uplinks, AWS (Advanced Wireless Services) and Satellite Telecommunications as described in my blog article entitled “Honeywell partners with Immarsat for In-Flight Satellite Broadband in 2013AD - Konshens Gal a Bubble for Qualcomm Airplane Broadband”.

So this development has me especially excited, as it means that future Telecom Networks can have the best of both worlds: higher Fiber Optic Bandwidths without expensive Fiber Optic infrastructure and reduce Spectrum License costs due to the use of Optical Frequencies to carry Backhaul Traffic to Cell Sites. This will make it cheaper in the future to roll out 4G LTE (Long Term Evolution) Networks and scale up for faster speed networks in the Future by using what is effectively FLORA Networks.

This is the eventual future of Terahertz Oscillator Research!