Skip to comments.'Quiet' light
Posted on 02/02/2019 7:04:53 PM PST by BenLurkin
DARPA was interested in creating a chip-scale laser optical gyroscope. Important for its ability to maintain knowledge of position without GPS, optical gyroscopes are used for precision positioning and navigation, including in most commercial airliners.
The laser optical gyroscope has a length-scale sensitivity on par with that of the gravitational wave detector, one of the most precise measuring instruments ever made. But current systems that achieve this sensitivity incorporate bulky coils of optical fiber. The goal of the OwlG project was to realize an ultra-quiet (narrow-linewidth) laser on the chip to replace the fiber as the rotation-sensing element and allow further integration with other components of the optical gyroscope.
According to Blumenthal, there are two possible ways to build such a laser. One is to tether a laser to an optical reference that must be environmentally isolated and contained in a vacuum, as is done today with atomic clocks. The reference cavity plus an electronic feedback loop together act as an anchor to quiet the laser. Such systems, however, are large, costly, power-consuming and sensitive to environment disturbances.
The other approach is to make an external-cavity laser whose cavity satisfies the fundamental physical requirements for a narrow linewidth laser, including the ability to hold billions of photons for a long time and support very high internal optical power levels. Traditionally, such cavities are large (to hold enough photons), and although they have been used to achieve high performance, integrating them on-chip with linewidths approaching those of lasers stabilized by reference cavities has proved elusive.
To overcome these limitations, the research team leveraged a physical phenomenon known as stimulated Brillouin scattering to build the lasers.
"Our approach uses this process of light-matter interaction in which the light actually produces sound, or acoustic, waves inside a material," Blumenthal noted.
(Excerpt) Read more at phys.org ...
INS: inertial nav system.
So is this supposed to be an improvement on the Sperry Mark XIV mod 1 that I first used? (Circ. 1944)
I can do this one!
I was very good at Orienteering!
Lets see if I can describe orienteering.
Well, you have a map.
A map is a two dimensional representation of.....its a piece of paper with squiggly lines and colors on it. You mostly use it to keep the rain off your head because it always rains when you go orienteering.
Now, you also have a compass. Not a geometry compass, but a compass with a needle and all the points. Lets see theres East and West and up and down or something like that.
The really professional orienteerers or staggering drunks as theyre sometimes called, use a lensatic compass. This is a compass with a little flip up dohicky that is used for.....well I dont know what you could possibly use it for. Maybe to flip the top on a beer can.
Us regular orienteerers or cheapskates as were commonly called, use a clear plastic compass that you can put on the map if its not too soggy and see all the colors.
Charles Stark Draper would have loved this.
Nothing’s quieter than Library light.
“Our approach uses this process of light-matter interaction in which the light actually produces sound, or acoustic, waves inside a material”
hmmm. sounds sort of like a photon cavitron ...
All the colors on the map stand for something.
Blue, of course, stands for water.
Green stands for vegetation.
Yellow stands for you dripped some mustard from your ham sammich on the map.
Puce stands for gay bars. You wouldnt think there would be a lot of gay bars out in the woods, but evidently, homosexuals are hikers.
One of the first things you have to do is orientate your map. You ask the map if its a boy map or a girl map or a gazetteer or something.
You have to use the declination diagram that is on the map.
It turns out that North isnt really North. Sometimes East is North. It has something to do with the North Pole. Rudolph screws up compasses or something.
Anyway, you have to know the declination in degrees. Sometimes its a bachelors degree and sometimes its a masters degree.
You have to be able to convert Fahrenheit degrees to Celsius degrees.
Most of the time, you just add five degrees to whatever bearing you have to go on.
Say....you’re Captain Spaulding, the African explorer, aren’t you?
Ping for your input.
So, you figure out your bearing, and then you grease it.
Theres a lot of bearing greasing going on where the puce is on the map.
But you are walking and you have to figure out how many steps you need to take to get to your first point. Thats why you have already figured out your Step Count.
A Step Count is how many steps you take to go 100 meters. You lay out a 100 meter tape and then walk beside it and count your steps.
But steps can be tricky things. You probably have to step over fallen trees and moose crap and homosexuals greasing their bearings.
So you have to have an Adjusted Pace Count. Hopefully its a well adjusted pace count and doesnt need therapy.
Ill stay a week or two
Ill stay the summer through
But, I am telling you
I must be going.
Hooray for Captain Spaulding the African Explorer!
Did someone call me schnorer?
Now you have your bearing and you know how many steps to take!
Youre ready to go......have a drink from the old wineskin.
Theres lots of drinking from the old wineskin in orienteering.
I used to carry four or five wineskins.
After a while, you learn that the real fun in orienteering is not galloping through the bushes looking for some pole or Italian, but hitting the old wineskin.
I dont think I ever found a single point.
I would drink four or five wineskins of wine and sit down on a stump and start singing Muskrat Love or some other hiking song and wait for the helicopter to find me.
But, alas, orienteering has fallen on hard times.
Where before, millions of orienteerers were tramping through the woods singing Muskrat Love, you can now barely find a half dozen tramps in the woods. But I keep searching.
I blame this falloff of orienteering on, you guessed it, PMS....Global Positioning System.
Now, you just ask your car where to go and it tells you how to get there. And it doesnt swear near as much as my Dad did when I was driving with him.
How the hell would I know where the museum is? Have you got another wineskin?
This is why I strongly urge everyone to turn off their PMS systems and go into the woods looking for tramps. And I dont mean hobos!
This is exactly the chip scale atomic or as another name quantum gyros and accelerometers that make long term miniature nearly perfect CEP inertial navigation system possible. The fact that they are mentioning this in the public sector is proof that it is already at the production point for black systems.
Since I always had to have the helicopter rescue me, I became friends with a few helicopter pilots.
I asked them how they navigate.
You just have to get up high enough to see the Pacific Ocean. If I can see the Pacific Ocean, I can find my way anywhere.
I asked them what they did at night.
Oh, we dont actually fly at night. We turn on the engine and let those flat things whirl around a bit, but we dont actually take off in the dark.
Thanks, enjoyed. Pretty sure that is the one I saw 50+ years ago.
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