Traditional optical tweezers rely on the use of continuous-wave laser sources with moderate to high optical powers, leading to unwanted thermal effects. Here, we demonstrate that a femtosecond laser can provide optical tweezing of microparticles using an average power as low as 80 uW.
When using the Space-Time light sheet, the interferometer exhibits 23% higher phase stability compared to the Gaussian light sheet (GLS), and 80% higher stability when compared to the Gaussian beam (GB). We find that while both ST light sheet and GLS exhibit significantly higher phase stability than the GB, ST light sheets have the added advantage of being resistant to speckle generation when a thin diffuser is inserted in the interferometer. Additionally, we show that interferometry using the ST light sheet results in approximately 11× more accurate measure of an oxide thickness on the substrate than the Gaussian beam. Our findings provide a simple approach to improving the stability of optical interferometry for applications, such as high-precision length measurements, enhanced sensing, and quantum optical experiments
Read more here
Jillian Sun’s work presents a new way to monitor two-photon lithography nanoscale fabrication could help improve the accuracy and efficiency of creating 3D engineered tissue scaffolds, according to a new study. Tissue scaffolds mimic the natural extracellular matrices found in the body, which creates a 3D environment ideal for tissue formation.
The article can be found here
Our recent tutorial on reversible optical coherence conversion was highlighted in the Editor’s Pick collection in Journal of Optics!
This work introduces the concept and experimentation of reversible optical coherence conversion, and outlines optical coherency matrix tomography as a method for measuring the full coherence of a field. To date, coherence conversion has only been demonstrated between the spatial and polarization degrees-of-freedom (DoFs). Coherence conversion offers a new control over an optical field’s DoFs—protecting against deleterious scrambling effects.
To read more, click here.
The NPR news reported our work in pulse oximeter and the article together with an audio could be found here: ‘When it comes to darker skin, pulse oximeters fall short‘. The article showed our opinion that the commercial devices have been shown in research to produce inaccurate results in dark-skinned people, and our lab is developing technology that would be more accurate, regardless of skin tone.
Our pulse oximetry work that aims to take racial bias out of oxygen readings by using a single wavelength of light that bypasses the skin is reported by Boston Globe, titled ‘A blood-oxygen detector without racial bias‘. Having completed preliminary testing, we intend to start clinical trials in a couple of months to confirm that their prototype eliminates skin-color bias.
A prototype of the pulse oximeter
An interdisciplinary group of experts came together at Brown University for the second in a series of Home Health Technologies in 2032 meetings, namely Workshop 2: Healthcare Technologies in the Living Environment, to explore how emerging technologies might better support improved health and well-being without ever leaving home. Over the course of a day and a half in early June, working groups made of up varying stakeholders identified how in-home tech could drive paradigm shifts in healthcare, paying particular attention to solutions that would reduce the load on healthcare systems, address accessibility and equity for all populations and could realistically be translated into the home itself within ten years.
For more details about the event, please visit: https://engineering.brown.edu/news/2022-06-14/hht-32-part-2
Pulse oximeters can overestimate blood oxygen in people with dark skin. Rutendo Jakachira, a PhD student in our lab, aims to use a single wavelength of light to bypass the skin. Recently her work got cited in an article in Politico titled ‘Flawed oxygen readings may be behind Covid-19’s toll on people of color’.
Rutendo Jakachira, a second-year Ph.D. student in Brown University’s Department of Physics, has received an inaugural Optica Foundation Amplify Scholarship. Jakachira was one of only fifteen students selected from around the world for the award, intended to “support Black students and their passion for light science.”
Jakachira will use the funds to continue working on a project with considerable implications for people of color around the world. For years it has been known that patients with darker skin receive less accurate blood oxygen measurements using pulse oximeters than those with lighter skin. Jakachira, in conjunction with Brown University Professor of Engineering Kimani C. Toussaint, is working to create a non-invasive method of obtaining accurate blood oxygen readings from people with darker skin.
On Feb. 17 and 18, Brown University hosted a workshop to explore the technological challenges and opportunities presented by this massive shift to home-based care. Titled Home Health Technologies in 2032, the event gathered more than 90 physicians, biomedical engineers, technologists, social scientists and others for virtual meetings.
The workshop’s organizing committee included Professor Toussaint along with other Brown engineering faculty members.
Professor Toussaint said the goal was to bring medical experts together with technologists to help plot the course of home health care over the next decade.
“We need to think about what kinds of technologies are needed most — whether for diagnostics or therapeutics or some combination of the two — and how these technologies could interface with the existing health care infrastructure,” Toussaint said. “At the same time, it’s critical that we start thinking right from the very beginning about how to make these technologies affordable and accessible to everyone, so that we’re not perpetuating existing disparities or creating new ones. The idea is to develop a roadmap for how these technological changes will unfold over the next 10 years.”
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