Can a microwave signal be pulsed at a IR frequency?

Question

This might relate to a question, are more than one photon packets in each wave cycle, but that is not my interest and I probably could not understand the answer.

This is connected to solving the problem of roadside bombs in Iraq. If a microwave signal could be pulsed at a IR frequency at a metal container having plastic explosives as its contents would an ultrasound signal (a mechanical wave) at the IR frequency vibrate the container? If so, if the ultrasound vibrations were at the same frequency of the peak IR absorption band of the N-N02 molecule would enough energy be generated in enough molecules to start a chain reaction to blow up the device well away from our troops.

Lacking much knowledge on these subjects my imagination is not hampered by the facts.

Answer 1

Dear Interested Party:
Your question asks if a microwave frequency (presume 2 to 6 Ghz) be pulsed at IR rates... No, it cannot, in my estimation. That is to say, when the modulation or pulsing rate is exceeds the base frequency of oscillation by several orders of magnitude, you enter an area called broadband white noise. For all practical purposes I believe these kinds of emissions to be undefined. For example, the oscilation frequency of "Infrared Light" is many orders of magnitude greater than 4 Gigahertz.

Also, the pulse rate is not the killing factor in microwave energy. The killing factor is energy within the pulse (peak power in watts).That means that the pulse length comes into account. If you lengthen the pulse to deliver suitable power to be destructive, you slow down the rate at which the pulses may be applied to the transmitting device (remember the modulation frequency is many magnitudes greater than the base frequency - your question). If you do not slow down the pulse rate, the pulses would overlap yielding continuous signal - not pulse.

Searching back through my educational background I cannot recall ever hearing about a modulating frequency that was higher than the base oscilator frequency. So, I do not think it can be done.

In reality, were you seaking to destroy roadside bombs with pulsed microwave energy, suitable radar sets already exist which could blow those devices to smithereens by virtue of RF heating. The problem is that you would also kill civilians in the nearby vicinity or deliver serious RF burns to them I think.

Answer 2

Infra red is much higher frequency than microwaves. So no you cant. You could modulate infra red at a microwave frequency.

Your goal is worthwhile. But you need a much better understanding of physics. I think if you read Feynmans lectures
http://www.amazon.com/gp/product/0201021153/ref=pd_lpo_k2_dp_k2a_2_txt/002-5739560-3156800?ie=UTF8
you will be well on your way. He is probably the only lecturer that explains well enough to read on your own. You may have the odd question but then there are resources at school and on the internet for queries.
Best of luck
PS nuclear magnetic resonance may be a better attack upon your project. That and sniffing.

Answer 3

"Lacking much knowledge on these subjects my imagination is not hampered by the facts."

You got **that** right☺


Doug