Why don't the people "in the know" want to comment?

What if you started a blog, and nobody cared? Well, we haven't reached quite that level here, but the lack of interest in posting anything substantive about terahertz or which is really informative, is becoming quite pronounced. I have asked numerous people involved in terahertz for comment, but very little response has materialized. If people in the know don't want to post here, please consider starting your own blog. In fact, that might be preferable. I just want discussion, commentary, a place to ask questions. Having said this, I recognize that the people in the know, do have their journals and resources such as the virtual thz journal I linked on the home page here. It's probably wishful thinking that they would want to discuss their ideas in public which are often proprietary, but at least I'm trying to open up such a discussion forum.

What are the technical limitations and problems that keep terahertz from moving firmly from the research lab to industrial floors. My sense is that is that it is cost, and need to demonstrate a proven return on the significant investment, before any industry (other than the US government -ie NASA) comes on board. However, once the tap gets started it's going to significantly increase in volume. When is this likely, and with what product platform.? Those are the big questions in my mind.
Perhaps part of the problem with this blog, arises from my lack of expertise in the science surrounding the topic, and some of my prior posts may have appeared naive or simply unintelligible, to those involved with Terahertz. If so, then it's regretable, because this remains an interesting topic, and I continue to invite anyone with a background in terahertz to post. So far, only Dr. Mittleman, at Rice University, has taken any time to help some of us better understand developments in Terahertz, so we can spread the word, and for some us, help with investment opportunities that currently exist. Thank you yet again, Dr. Mittleman.
I learned earlier this week during my questions on the Advanced Photonix, (API) conference call, that the 145 million dollar Darpa contract with Teledyne, which is to be used to develop terahertz electronics for transceiver arrays, (which was posted on May 17th here: http://terahertztechnology.blogspot.com/2009/05/questions-about-futurecontinuous-wave.html )really is not about terahertz (in a conventional sense) at all. At least, it doesn't involve the development of a machine which will bear any real relationship to the Advanced Photonix T-4000.
So, my earlier post, displayed my confusion about the development of the technology, and a total lack of comprehension about the nuances.
Anyone involved with Terahertz development is welcome to post their comments and insights by emailing me at knudson.randy@gmail.com.

In the meantime, I have joined the facebook Thz group, which is found here:
http://www.facebook.com/home.php#/group.php?gid=21589817360 .

I found it interesting that there are other terahertz groups on facebook including
Virginia Diodes (http://www.virginiadiodes.com/) which has their own page here:
http://www.facebook.com/home.php#/group.php?gid=39310257521.

So, one last time. Help me, get some intelligent word (for a change), out about developments and opportunities to be found in the virgin field of Terahertz .

Questions about the future:Continuous wave Terahertz vs Time Domain Terahertz

A number of recent multi-million dollar contracts with the Federal Government, (Darpa) which involves continuous wave terahertz (CWT) makes me question, if time domain terahertz (TDT) has proven to be too difficult to employ, or has reached some type of technical barrier which prevents or limits it's usefulness. I certainly, don't know the answer to this question and hence I am hoping to invoke some comment from someone who might know.

The following is a news article, (actually the latest in a series) which discusses the development of CWT.

I'm hoping Dr. Mittleman or someone else that is knowledgeable might comment on the limitations found in TDT, and why CWT appears to have gained such recent attention.
Thanks for any comments



DARPA looks to Teledyne Scientific for terahertz electronics researchARLINGTON, Va., 10 May 2009. Researchers at the U.S. Defense Advanced Research Projects Agency (DARPA) are looking to Teledyne Scientific & Imaging LLC in Thousand Oaks, Calif. to develop terahertz electronics receivers and exciters as part of the DARPA Terahertz Electronics Program.Teledyne Scientific won an $8.3 million DARPA contract to develop terahertz electronics for transceiver arrays -- specifically, receivers and exciters at carrier frequencies of 670 GHz, 850 GHz, and 1030 GHz.U.S. Department of Defense officials anticipate that terahertz integrated circuit technology will provide major advancements for military applications in advanced military imaging technology, radar technology, terahertz spectroscopy for chemical warfare detection, and military communications.Teledyne Scientific joins Science Applications International Corp. (SAIC) in San Diego, the Northrop Grumman Electronic Systems segment in Linthicum, Md., and the Northrop Grumman Space and Mission Systems segment in Redondo Beach, Calif., in performing research on the DARPA Terahertz Electronics initiative.The sub-millimeter wave (sub-MMW) frequency band between 0.3 to 3 terahertz historically has been extremely difficult because designers lack the means to generate, detect, process, and radiate radio-frequency (RF) signals in these frequencies, DARPA officials explain.Military and aerospace applications that operate at terahertz frequencies need greatly improved terahertz transmitter and receiver technologies to be effective. That is where Northrop Grumman and SAIC experts come in.For transmitters, DARPA primarily wants to develop higher power sources and amplifiers -- with acceptable wall-plug efficiency, instantaneous bandwidth, and gain -- than are available today.DARPA experts say they have an opportunity improve noise figure and phase noise characteristics in future terahertz RF applications. Signal-to-noise ratio improvements of 70 decibels or more might be possible with spectral filtering and phase coherent processing techniques such as using coherent heterodyne processing that exploits the relative phases of transmit and receive signals.A big drawback to terahertz electronics has been the lack of high-density integrated circuit technology. Achieving the level of integration necessary to enable practical terahertz systems, such as arrays, will require SAIC and Northrop Grumman to come up with methods for integrating devices into compact circuits.In charge of this project is the DARPA Microsystems Technology Office (MTO). Supervising the program will be DARPA Program Manager Mark Rosker, who can be reached by e-mail at mrosker@darpa.mil, or by phone at 571-218-4507.For more information contact the DARPA Microsystems Technology Office online at www.darpa.mil. http