Category: Oral Presentation

Hannover Universität, Hannover, Germany

March 9, 2023 @ 3:30pm in Empore Lichthof F102

Group report: Precision spectroscopy and quantum information with trapped molecules

Brandon J. Furey, Stefan Walser, Zhenlin Wu, Guanqun Mu, Rene Nardi, and Philipp Schindler

Universität Innsbruck

The quantum molecules group at the University of Innsbruck utilizes a range of innovative advances in molecular spectroscopy and quantum logic spectroscopy (QLS) to study molecular rovibrational structure and explore quantum information processing with trapped molecules. The efforts of our group are divided into three projects. The first is pump-probe recoil spectroscopy, where we measure the rovibrational population dynamics excited by a pump pulse by mapping them to the electronic state of an atomic ion via QLS. The second project investigates state-dependent force spectroscopy, where an optical tweezer generates a state-dependent force on a trapped molecule. Our third project is demonstrating superpositions of rotational states in a diatomic molecular ion built using stimulated Raman transitions driven by two beams from an optical frequency comb. This could pave the way for using quantum error correction to realize the use of trapped molecules for quantum information or memory. We are interested in creating the rotational superposition states that form the codewords of a truncated Z3 ⊂ Z6 linear rotor code. In order to demonstrate ultrafast light-matter interaction in our system, we have measured the photodissociation spectrum of CaOH+ using an optical parametric amplifier.

MO 17.5
3:30 PM–3:45 PM, Thursday, March 9, 2023
Empore Lichthof F102

Link to more information: https://www.dpg-verhandlungen.de/year/2023/conference/samop/part/mo/session/17/contribution/5

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Universitätszentrum Obergurgl, Austria

August 23-27, 2022 in Konferenzen Raum

QCosmo

Zhenlin Wu, Brandon Furey

Universität Innsbruck

We present an update and overview of our project’s milestones in the last year and proposed experiments in the upcoming year. We explain the motivation for studying trapped molecules and discuss the experimental setup including the vacuum chamber upgrade, rack-based laser system, ion loading, and the frequency comb. We then present preliminary results from our photodissociation experiment with CaOH+. Finally, we discuss the outlook of our project over the coming years; our plans to load molecular ions with a leak valve, photoionization, and ion optics, as well as cat-state spectroscopy, state-dependent force spectroscopy, and Raman rotational spectroscopy.

QCosmo Session
11:30 AM–12:00 PM, Saturday, August 27, 2022
Konferenzen Raum

Link to QCosmo project website: https://www.quantum-molecules.eu/

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Centro de Investigaciones en Optica, Leon, Mexico

September 17, 2019 @ 11:00am

Two-photon absorption spectroscopy and anisotropy of silicon quantum dots and bulk semiconductors

Brandon J. Furey¹

¹University of Texas at Austin

Nanocrystalline silicon (Si) exhibits optical properties of quantum dots (SiQDs) that differ from bulk Si, including efficient emission of photoluminescence (PL). The peak PL wavelength varies with the size of the SiQDs. In addition, SiQDs are biologically inert and thus have potential applications in bioimaging. Recent research also shows that they can potentially be useful for cancer therapy by selectively targeting cancer cells and disrupting them with shock waves from collapsing bubbles formed when the SiQDs are strongly excited and heated to very high temperatures. For biological theranostic applications, it is preferable to excite the SiQDs by two-photon absorption (2PA); this allows excitation with lower-energy infrared photons which have deeper penetration depth in biological samples, and enables localizing the excitation volume in 3D by focusing the beam and exploiting the nonlinear intensity dependence of 2PA. We seek to map the size- and spectral-dependence of 2PA in SiQDs to identify spectral resonances using two-photon induced PL and pump-probe modulation spectroscopy (PPMS). We also study 2PA spectra and anisotropy in bulk Si (and other semiconductors) using z-scan and PPMS and are developing a model for relating the bulk response to the nanocrystalline response.

Link to host institution: https://www.cio.mx/

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Boston Convention Center, Boston, Massachusetts

March 7, 2019 @ 12:03pm in BCEC Room 204B

Two-photon spectroscopy and polarization dependence of Gallium phosphide

Brandon J. Furey¹, Rodrigo M. Barba-Barba², Alan Bernal², Ramon Carriles², Bernardo S. Mendoza², Michael C. Downer¹

¹University of Texas at Austin, ²Centro de Investigaciones en Optica

The two-photon absorption (2PA) coefficient of Gallium phosphide (GaP) was measured by open-aperture z-scan in the spectral range 650 – 1200 nm. Anisotropy in the polarization dependence of 2PA is then used to determine the two independent components of the imaginary part of the third-order nonlinear susceptibility tensor corresponding to the zinc blende crystal structure of GaP. These results are then compared to first-principles calculations using length gauge theory. The strong 2PA in GaP qualifies this material to be used as a reference when extending this experimental and theoretic technique to other crystal and nanocrystal materials.

Session S33: Semiconductors and Applications II
11:15 AM–2:15 PM, Thursday, March 7, 2019
BCEC Room: 204B

Sponsoring Unit: FIAP
Chair: Thomas Vandervelde, Univ of Virginia
Abstract: S33.00005 : Two-photon absorption spectroscopy and polarization dependence of Gallium phosphide*
12:03 PM–12:15 PM

My meeting notes: https://drive.google.com/file/d/1kVH2Y4JX0QOLiYohKTrR0bWyPV1sXHSk/view?usp=sharing

Link to more information: https://meetings.aps.org/Meeting/MAR19/Session/S33.5

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Gustavus Adolphus College, Saint Peter, Minnesota

February 12, 2018 @ 7:30pm in Olin 220

Nonlinear Optics of Silicon Nanocrystals and Physics at the University of Texas at Austin

Brandon J. Furey¹

¹University of Texas at Austin

Link to host department: https://gustavus.edu/physics/

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New Orleans Ernest N. Morial Convention Center, New Orleans, Louisiana

March 13, 2017 @ 8:48am in Room 299

Measurement of two-photon absorption cross section of silicon nanocrystals in colloidal suspension

Brandon J. Furey¹, Michael C. Downer¹, Dorothy A. Silbaugh¹, Adrien C. Guillaussier¹, Yixuan Yu², Brian A. Korgel¹

¹University of Texas at Austin, ²Lawrence Livermore National Laboratory

Two-photon absorption (2PA) in liquid suspensions of ligand-passivated silicon nanocrystals (ncSi) is difficult to measure directly because of their low absorption cross section and competing nonlinear optical processes at high light intensity. Here we overcome these difficulties by measuring background-free, 2PA-induced photoluminescence (PL) as a function of the intensity of ultrashort 800 nm excitation pulses and then calibrating the response by measuring PL induced by one-photon absorption. Using this indirect method, 2PA cross sections of ncSi with diameters 2.2 and 2.7 nm suspended in toluene were 0.505 ± 0.005 and 2.24 ± 0.02 E-50 cm4 s / photon, respectively. This procedure was validated using rhodamine B in ethanol for which the 2PA cross section was 21.8 ± 0.1 E-50 cm4 s / photon, which agrees with direct measurements.\footnote{A. Nag, D. Goswami, J. Photochem. and Photobio. A: Chem. 206 (2-3), 188 (2009)} The size dependence of 2PA cross sections for ncSi and comparisons with other reference samples will be discussed. Water-dispersible ncSi may be suitable for bio-imaging.\footnote{C.M. Hessel, J. Wei, B. Korgel et al., Chem. Mater. 24 (2), 393 (2012)} This application is demonstrated using 2PA confocal microscopy of ncSi-incubated mouse tissue.

Session A36: Quantum Dots, Quantum Wells, and Metamaterials: Optical Characterization and Applications
8:00 AM–11:00 AM, Monday, March 13, 2017
Room: 299

Sponsoring Units: DCMP DMP
Chair: Brennan Pursley, Naval Research Laboratory

Abstract ID: BAPS.2017.MAR.A36.5
Abstract: A36.00005: Measurement of two-photon absorption cross section of silicon nanocrystals in colloidal suspension*
8:48 AM–9:00 AM

Link to more information: https://meetings.aps.org/Meeting/MAR17/Session/A36.5

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Baltimore Convention Center, Baltimore, Maryland

March 14, 2016 @ 11:27am in Hilton Baltimore Room: Holiday Ballroom 5

Two-photon absorption in 3-100nm diameter Silicon nanocrystals in solution

Brandon J. Furey¹, Michael C. Downer¹, Y. Yu¹, Brian A. Korgel¹

¹University of Texas at Austin

Silicon nanocrystals (nc-Si) exhibit efficient photoluminescence (PL) that has applications in non-toxic bio-imaging. Two-photon absorption (TPA) is an important process for exciting PL in the tissue transparency spectral window, but absolute TPA coefficients have not been measured as a continuous function of nc size or excitation wavelength. Previous TPA studies have focused on nc-Si embedded in an oxide matrix or on porous Si surfaces at selected discrete wavelengths [1]. However, recently free standing, ligand-stabilized nc-Si with diameters ranging from 3 to 100 nm that are soluble in liquids, including water, and suitable for bio-imaging have become available [3]. We will present calibrated TPA spectra for free standing nc-Si over a wide range of nc diameters, based on measurements with tunable femtosecond laser pulses. We will compare indirect TPA measurements based on collection and detection of PL with direct TPA measurements based on attenuation of the incident beam. [1] P. Zhang, Z. Zhang, K. Chen et al., Nanoscale Res. Lett. 9 (28), 1 (2014) [2] C.M. Hessel, J. Wei, B. Korgel et al., Chem. Mater. 24 (2), 393 (2012).

Session B54: Optical Properties of Semiconductor Nanostructures II
11:15 AM–2:15 PM, Monday, March 14, 2016
Hilton Baltimore Room: Holiday Ballroom 5

Sponsoring Units: FIAP DMP
Chair: Alexander Efros, Naval Research Lab

Abstract ID: BAPS.2016.MAR.B54.2
Abstract: B54.00002 : Two-photon absorption in 3-100nm diameter Silicon nanocrystals in solution
11:27 AM–11:39 AM

Link to more information: https://meetings.aps.org/Meeting/MAR16/Session/B54.2

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University of Texas at Austin, Austin, Texas

December 5, 2014 @ 4:00pm in Robert Lee Moore* Hall Room 5.104 (*now Physics, Math, and Astronomy Building)

Nonlinear Optical Spectroscopy of Silicon Nanocrystals

Brandon J. Furey¹

¹University of Texas at Austin

My current project is second-harmonic generation (SHG) and two-photon absorption (TPA) spectroscopy of ligand-stabilized silicon nanocrystals (ncSi), a new form of free-standing mono-disperse ncSi developed recently in Professor Brian Korgel’s chemical engineering group that can be dispersed in various liquid solvents, including water. Silicon nanocrystals embedded in solid oxides have been of interest to silicon photonics for many years because, unlike other forms of silicon, they luminesce efficiently. However, the microscopic mechanisms of luminescence remain controversial, in part because the difficult-to-characterize nano-interface of the ncSi plays an important role. A previous Downer student (Junwei Wei, PhD 2012) carried out a SHG study of oxide-embedded ncSi that revealed nano-interface-specific spectroscopic signatures that contributed to better understanding of this elusive nano-interface.

My proposed work aims in part to provide a comparative SHG study of ligand-stabilized free-standing ncSi. Raman spectroscopy by Korgel’s group and ours has already shown that absence of interface strain in free-standing ncSi causes important changes in their vibrational spectra, compared to their highly-strained, oxide-embedded counterparts. My proposed SHG study will probe corresponding differences in the electronic structure of the nano-interfaces.

A second scientific interest of free-standing ncSi is bio-imaging. Since ligand-stabilized ncSi are non-toxic, they can be attached to living organelles, which can be imaged via their photoluminescence. Unfortunately, the upper luminescing states must usually be excited by UV light, which damages cells and is not easily transmitted through tissue. For in-situ applications, I therefore propose to excite these states via TPA using near-infrared femtosecond light pulses, which are non-ionizing and much more readily transmitted through biological samples.

I will present details of the experimental procedure and preliminary results.

Link to host department: https://ph.utexas.edu/

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Gustavus Adolphus College, Saint Peter, Minnesota

May 4, 2012 @ 2:45pm in Nobel Hall Room 222

Development of a Time-of-Flight Mass Spectrometer Using Radial Extraction from a Linear Quadrupole Ion Trap

Brandon J. Furey¹, Jessie Petricka¹

¹Gustavus Adolphus College

The primary objectives were the development of a linear quadrupole ion trap (LQT) and a time-of-flight (TOF) mass spectrometer. The LQT functions by forcing ions into a stable trajectory controlled by radio-frequency electric fields. A general overview of the development and operation of the LQT will be discussed. The ions that are currently being studied are produced by laser ablation which produces a plume of multiple different molecules. In order to identify trapped ions, a TOF mass spectrometer was developed and assembled. The ions are radially extracted from the LQT with a particular energy and accelerated through the drift tube. By measuring the TOF, the mass of the ions can be determined. Further discussion of the TOF device and other projects will follow.

Link to abstracts: https://gustavus.edu/sigmaxi/SXSymp2009_files/documents/2012SymposiumAbstracts.pdf

Link to schedule: https://gustavus.edu/sigmaxi/SXSymp2009_files/documents/2012SymposiumSchedule.pdf

Link to more information: https://gustavus.edu/sigmaxi/research-symposia.php

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Gustavus Adolphus College, Saint Peter, Minnesota

April 25, 2012 @ 7:30pm in Olin Hall Room 220

Development of a Time-of-Flight Mass Spectrometer Using Radial Extraction from a Linear Quadrupole Ion Trap

Brandon J. Furey¹, Jessie Petricka¹

¹Gustavus Adolphus College

The research goals for the Atomic, Molecular, and Optical Physics Lab Group for 2011-2012 were twofold; to produce and trap molecular ions using laser ablation to load a linear quadrupole ion trap (LQT), and to develop a time-of-flight mass spectrometer to identify the trapped ions. Such cold molecule samples have applications in mass spectrometry, measurement of physical constants, and quantum state manipulation. Dan McDougal designed and built the LQT. This year, consideration of the necessary conditions to trap ions in stable trajectories resulted in successfully trapped ions. In addition, a time-of-flight mass spectrometer was designed and the preliminary stages were built.

Link to host department: https://gustavus.edu/physics/

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Moscone Center, San Francisco, California

December 7, 2011 @ 12:00pm at NASA Exhibit in Exhibit Hall

Comparing SEBAL and METRIC: Evapotranspiration models applied to Paramount Farms Almond Orchards

Brandon J. Furey^1, Sean C. Kefauver², Susan L. Ustin²

¹Gustavus Adolphus College, ²University of California at Davis

Link to program: https://hec.nasa.gov/news/AGU2011_program_final.pdf

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Gustavus Adolphus College, Saint Peter, Minnesota

November 30, 2011 @ 7:30pm in Olin Hall Room 220

Modeling Actual Evapotranspiration: Comparing the SEBAL and METRIC Models Using Remote Sensing Data

Brandon J. Furey¹

¹Gustavus Adolphus College

Link to host department: https://gustavus.edu/physics/

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University of Chicago, Chicago, Illinois

November 5, 2011 @ 9:00am

Comparing SEBAL and METRIC: Evapotranspiration models applied to Paramount Farms almond orchards

Brandon Furey¹

¹Gustavus Adolphus College

Link to more information: https://mathsciconsortium.org/event_information/2011-undergraduate-research-symposium-at-the-university-of-chicago

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