We have recently detected a beam of cold CH radicals from our cryogenic source using laser induced fluorescence at 431 nm.
Preliminary measurements indicate that the beam rotational temperature is ~0.5 K and the mean forward velocity is ~130 m/s. We will now work to both increase the flux and demonstrate optical cycling in CH.
We can now detect cold AlCl molecules using our UV laser to excite the X-A transition at 261.5 nm. Inside the source, we measure a peak optical depth > 4 and produce a beam of AlCl molecules containing ~4 x10^(11) molecules/steradian/pulse in the rovibrational ground state.
We're very grateful to the Hemmerling Lab at UC Riverside for sharing their experience producing AlCl via laser ablation.
Our next steps are to fully characterize the molecular beam and perform spectroscopy relevant to optical cycling in this species.
Phase 2 of our homebuilt UV laser system is nearing completion. We currently produce up to 1.8 W of laser light at 261 nm from our second bowtie cavity. This is a serious amount of continuous UV power!
Our focus on this experiment will soon shift to use this light to detect cold AlCl molecules from our cryogenic source.
We’ve recently started to produce our first ultraviolet laser light at 261 nm. We currently make ~50 µW of UV light using 1.5 W of green through a single-pass of our nonlinear crystal. There’s still lots to optimize but this is a great first step!
In the near future we will close and stabilize the length of our bowtie cavity. This will realize significantly higher green light intensities and enable more efficient frequency-doubling.
Phase 1 of our homebuilt UV laser system is almost complete. We currently frequency-double 10 W of infrared laser light into 6 W of green. Congratulations Jamie on all of your hard work!
Next up, in phase 2, a second frequency-doubling stage will produce light in the ultraviolet. Stay tuned to learn more…
Our work realizing a new cryogenic source design for cold, slow molecular beams has been published in Phys. Rev. A.
This source can produce bright, continuous beams of molecules via ablation at 55Hz, provided that the He buffer gas flow ≥ 10 standard cubic centimeters per second.
We have recently detected the first CH absorption signals within our cryogenic source using the X-A transition at 431nm.
This feature shows that we make 6 x 10^(11) molecules per ablation pulse in the rovibrational ground state when ablating an iodoform target. We detect similar features when ablating cold paraffin wax.
Making a CH ablation target 101.
CH is highly reactive and therefore challenging to produce. One direction we’re pursuing is a variant of the Lewandowski/Weinstein method using iodoform from this paper.
Our initial work with SrF molecules is over. We’re now working towards producing and detecting cold beams of AlCl and CH radicals.
The first step is the mass production of Fabry-Perot cavities and external cavity diode lasers. These parts, combined with our HeNe reference lasers, will allow us to define the frequencies of our lasers to better than one part in 100 million.
The ongoing COVID-19 pandemic means that new equipment is received at home rather than the lab. It’s a little strange having our new electron-multiplying CCD camera on my kitchen counter…
We recently confirmed that our second cryogenic source is working by producing pulses of our test-species, SrF. Here we detect molecules in X(v=0, N=0) via the absorption of resonant laser light.
We produce ~10^(11) molecules in this rovibrational state per pulse and can now move on to work with CH molecules.
Several of our large optical breadboards required through-holes to allow us to mount them in the new lab.
Thanks to Ray Celmer in our machine shop for making this happen!
A frequency doubled M-Squared SolsTiS laser arrived this month. This tunable laser system can emit light between 700 – 1000 nm and 350 – 500 nm. This light will be invaluable for our initial spectroscopy on CH molecules and for exciting specific transitions in AlCl molecules.
Sadly, the box must remain closed until an M-Squared technician is on site…
Our second pulse tube refrigerator is now installed in our latest cryogenic source for experiments using CH radicals.
This source reaches a lab-record low- temperature of ≈ 2 K!
Our new and improved HeNe reference laser is ready to test. Various lasers in our lab are stabilized to this reference via broadband transfer cavities.
Edit: Spectroscopy on our molecular beam shows that this laser has been stable to ~1 MHz over the past 4 months.
Our new lab is starting to look and feel more like home now that we have our optical tables in place.
A photo of our spectroscopy system being moved to the new lab while at a pressure of ~10^(-8) Torr.
Thanks to G&F Moving for getting this, and our other optical tables, transported safely.
Special thanks to Whiting-Turner for “modifying” the door frame to our old lab.
This allowed our cryogenic source to move into our new space as-is and saved us a lot of time.
The finishing touches are being applied to our new space as we continue to pack.
A big welcome to new graduate student Joey!
You’ve joined us just in time to help disassemble and pack our current experiment in its temporary space.
Our new lab is taking shape although there’s still a lot to do…
We’ll begin moving in 3 months.
We recently attended our first DAMOP conference in Milwaukee.
Here we presented our research plans using AlCl and CH molecules alongside our initial results using SrF molecules.
Dan secures a prestigious CAREER Award from the National Science Foundation.
Learn more here.
First time-resolved laser-induced-fluorescence measurements made on our beam of SrF molecules. Each pulse of molecules has a duration of ~20 ms.
Jamie wins an award at the Physics Department annual research poster exhibit – congratulations!
Jamie’s poster presented our new cryogenic source alongside absorption and fluorescence measurements on a beam of SrF molecules.
Today we visited our future home in the new Department of Physics building at UConn. We expect to move into our new lab in about 6 months.
A photomultiplier tube will soon be installed above our molecular beam for sensitive tests of optical cycling in molecules. This specific device detects photons from 185 to 850 nm.
Our cryogenic source is operational! We’ve detected our first beam of SrF molecules via absorption.
The laser system and locking setup for our initial tests using strontium monofluoride (SrF) molecules is taking shape.
Our first vacuum system is now assembled and pumping down. This setup will be used for spectroscopy and optical cycling experiments on molecular beams.
Our pulse-tube refrigerator is insulated and working well! We can cool down to a minimum temperature of ≈ 2.2 K that’s stable to ± 5 mK.
Our first cryogenic source chamber is taking shape. We’ll be ready to test our pulse-tube refrigerator soon!