Latest News & Results

 Majumder Group News

October 2017

We are very happy to welcome new postdoc Dr. Daniel Maser to our group.  Dan completed his undergraduate degree at Berkeley, and his Ph.D. at the Univ. of Colorado, working in Scott Diddams’ lab at NIST building new frequency-comb-based mid-IR laser sources for sensing applications.

Dan will immediately join current thesis student Bingyi Wang ’18 as we complete our latest indium ABU polarizability experiment, and also continue our Pb transition amplitude / Faraday polarimetry work begun last year by Eli Hoenig ’17.

DAMOP 2017, Sacramento, CA June 5-9, 2017

A great week in Sacramento with lots of current and former students and colleagues!

Current Majumder group attendees:  Nathaniel Vilas ’17, Eli Hoenig ’17, Postdoc Milinda Rupasinghe,  Joined by Prof. Charlie Doret, three of his students, and Prof. Swati Singh.

     Receiving APS Prize w/current DAMOP chair Steve Rolston.

   At poster session with Nathaniel and Eli

  Ephs @ DAMOP 2017

  Current, former Majumder lab thesis students in attendance:
(L-R)  Eli Hoenig ’17, Nathaniel Vilas ’17, Nathan Schine ’13, Colin Bruzewicz ’05, Ben Augenbraun ’15, Charlie Doret ’02

Here are the posters we presented on the Pb and In experiments:
Pb Faraday spectroscopy / E2 transition measurement
In atomic beam polarizability measurements

May 2017

Congratulations to Eli Hoenig ’17 and Nathaniel Vilas ’17 who completed their senior theses describing excellent work and exciting new results in two experiments:

Nathaniel Vilas – two-step atomic beam spectroscopy / polarizability measurements of the indium 7p states:  Vilas Thesis (4 MB)

Eli Hoenig – Lead vapor cell polarimetry of both the 1279 nm M1 and 939 nm E2 transitions to measure absolute transition linestrengths:  Hoenig Thesis (6 MB)

February 2017

We have resurrected our optical polarimeter, with plans to measure the M1 and E2 ground-state transition amplitudes in Lead (comparing Faraday Rotation signals for a common magnetic field and in the same vapor cell) to test new atomic theory calculations.  Some pretty impressive measurements (thanks Eli!) of intrinsic angle noise at the 0.1 μradian / √Hz level:

Angle noise test with 940 nm laser

October 2016

Received this exciting news in a letter from the APS this week:

On behalf of the American Physical Society, it is my pleasure to inform you that you have been awarded the 2017 Prize for a Faculty Member for Research in an Undergraduate Institution:

“For contributions to the precision measurement of atomic properties, and sustained, inspirational mentorship of undergraduate researchers.”

This could not have happened without an institution committed to supporting research with undergraduates, as well as great colleagues, and, most of all, a wonderful and talented collection of Williams students with whom I’ve had the privilege of working for the past 20 years.  I’m very grateful!

Summer 2016

Group picture from summer (L-R:  Nathaniel Vilas ’17, PKM, Eli Hoenig ’17, Bingyi Wang ’18)

Rising thesis students Eli Hoenig ’17, Nathaniel Vilas ’17, as well as rising junior Bing Yi Wang ’18 and postdoc Milinda Rupasinghe completed a series of vapor cell spectroscopy experiments in thallium and indium using our two-step spectroscopy technique.  All the second-step transitions were in the red 650-690 nm range and so by exchanging diodes we measured hyperfine structure and isotope shifts all with sub-MHz accuracy.  This work is now being written up for publication.

Meanwhile, our paper describing the latest atomic beam polarizability measurement (in the indium 6p1/2 excited state) was published in Phys. Rev. A  in August with Ben Augenbraun ’15 and Allison Carter ’16 as co-authors.

June 2016

Congratulations to Allison Carter ’16, and Sauman ’16 who graduated on June 5th, and completed very successful senior thesis projects in the lab this year!  Good luck to Allison, who is starting in the Physics Ph.D. program at U. Maryland, and to Sauman, who is starting in the Mech. Eng. Ph.D. program at U. Colorado this fall.  We will miss you!


This year’s theses:
Allison:  indium 6p1/2 state polarizability measurement  using the atomic beam (2.7 MB)
Sauman:  thallium 8p1/2-state HFS/ IS shift work using the heated vapor cell  (8.4 MB)


Oh — and something to make me feel old:  Picture of my very first set of thesis students who returned this June for their 20th reunion!! (Kyle Downey ’96, Paul Boerner ’96):

DAMOP 2016, May 23-27 2016, Providence, RI

The proximity of this year’s DAMOP conference allowed Profs. Doret and Majumder to fill up a van with Ephs and drive.  Accompanying them were graduating seniors Allison Carter ’16, Sauman Cheng ’16, and Ariel  Silbert ’16.  Also attending were Nathaniel Vilas ’17 and Sierra Jubin ’17, who will be starting thesis work this summer, and also postdoc Milinda Rupasinghe.

Ben Augenbraun ’15 attended the conference, and formally received his 2015 APS Apker Award certificate, and gave an excellent invited talk on his thesis work.

Many other Ephs (19 in all!) were in attendance (spanning more than a half century of graduating classes!):


Here are all of the current and former Majumder group thesis students in attendance:


(L-R) Allison Carter ’16 (U. Maryland), Nathaniel Vilas ’17, Sauman Cheng ’16 (U. Colorado), Ben Augenbraun ’15 (Harvard), Charlie Doret ’02 (Harvard, GTRI, Williams!), PKM, Colin Bruzewicz ’05 (Yale, Lincoln Labs), Nathan Schine ’13 (U. Chicago), Paul Hess ’08 (Harvard, U. Maryland).

And here we are at the poster session with our two group posters behind:


PDFs of posters presented:
Indium 6p1/2-state Atomic Beam / Stark shift measurement
Thallium 8p/12-state HFS/IS spectroscopy
October 2015

Congratulations to thesis student Ben Augenbraun ’15 who is the 2015 A.P.S. LeRoy Apker Award  WINNER !!! (the Apker Award is the nation’s top honor for undergraduate physics research).  We wish Ben the very best as he begins in the Ph.D. program at Harvard this fall.  

Former group member, and now Williams physics department colleague, Charlie Doret ’02 was the 2002 Apker Award winner.  All together FIVE Williams physics majors have won this award.

Here is a link to Ben’s undergraduate thesis:
Augenbraun thesis (6.2 MB)

June, 2015

We welcome Sauman Cheng ’16 and Allison Carter ’16 to the lab this summer , who will begin their thesis work, and will be joined by Nathanial Vilas ’17, Milinda, and Prof. Majumder.

Here is a picture of the summer 2015 research group:


DAMOP 2015, Columbus, OH:
Ben Augenbraun ’15, Postdoc Milinda Rupasinghe, and Prof. Majumder attended the 2015 DAMOP conference in Columbus, OH.  Here are some highlights:

Ben Augenbraun ’15, Nathan Schine ’13 and PKM in front of latest group poster on two-step, atomic beam Stark shift experiment in Indium.

Ephs@DAMOP 2015: (L-R) Ben Augenbraun ’15,Dr. Justin Brown ’05 (Draper Labs), Paul Hess ’08 (Harvard, JQI), Colin Bruzewicz ’05 (Yale, Lincoln Labs),Prof. Charlie Doret ’02 (Harvard, Williams College), Dr. Milinda Rupasinghe (postdoc, Majumder group),Nathan Schine ’13 (U. Chicago),Ryan Carollo ’05 (U. Conn), Prof. Chad Orzel ’93 (Union College), PKM, Prof. Josh Grossman ’96 (St. Mary’s College)

Former Majumder group thesis students @ DAMOP: Paul Hess ’08 (Harvard), Ben Augenbraun (Harvard), Charlie Doret (Harvard), Nathan Schine (Chicago), Colin Bruzewicz (Yale)

Winter/Spring, 2015
Welcome to new postdoc, Dr. Milinda Rupasinghe, who joined us in January from Oklahoma, where he did his Ph.D. work in atomic physics.

 We gratefully acknowledge the support of our new 3-year NSF grant #1404206 which supports our postdoc, summer studies, and equipment and supply needs.


DAMOP 2014, Madison, WI:
Here is the latest from our group, including recent photos, DAMOP 14 conference posters, senior honors theses, and publications    

Ephs@DAMOP 2014: (L-R) Prof. Chad Orzel ’93 (Union College), Prof. Josh Grossman ’96 (St. Mary’s College), Prof. Charlie Doret ’02 (Williams College), PKM, Nathan Schine ’13 (U. Chicago), Dr. Justin Brown ’05 (Draper Labs), Ryan Carollo ’05 (U. Conn), Ben Augenbraun ’15

Nathan Schine ’13 (now at U. Chicago) and Ben Augenbraun ’15 at Poster Session w/indium atomic beam poster, DAMOP 14.

POSTERS FROM DAMOP 2014, Madison, WI, June 2-5
Atomic Beam / Stark shift poster  (2.8 MB)
Vapor Cell / 2-step Spectroscopy poster (3.8 MB)



  • Senior Honors Thesis of Allison Carter ’16 (now at U. Maryland): Carter thesis (2.7 MB)
  • Senior Honors Thesis of Ben Augenbraun ’15 (now at Harvard Univ.):  Augenbraun thesis (6.2 MB)
  • Senior Honors Thesis of Nathan Bricault ’14 (now at Cambridge Univ): Bricault_thesis
  • Senior Honors Thesis of Nathan Schine ’13 (Simon group, U. Chicago):   Schine_thesis

Phys. Rev. A paper describing this work:



  • Senior Honors Thesis of Sauman Cheng ’16 (now at U. Colorado): Cheng thesis 
  • Senior Honors Thesis of Gabby Vukasin  ’14 (now at Tufts Univ):     Vukasin_thesis
  • Senior Honors Thesis of David Kealhofer ’13 (now at UCSB):    Kealhofer_thesis

 Phys. Rev. A paper describing this work: