MIT Media Lab and OLPC

In 2005 Jepsen joined the faculty of the MIT Media Lab as a professor with a tenure-track position. Here she started the Nomadic Displays Group, and co-created the first holographic video system in the world in 1989, where the interference structure of the hologram was computed at video rates, and shown on her hand-made display.^[13] This system inspired a new subfield of holographic video and received numerous awards.^[14]

Working with Nicholas Negroponte, she simultaneously co-founded One Laptop per Child, a $100 computer, the lowest-power laptop ever made. As of 2013, millions of units have shipped to children in the developing world and revenues are beyond the billion dollar mark. There are deployments in over 50 countries and in more than 25 different languages.^[15][16] For the entire first year of the effort (2005) she was the only employee of One Laptop per Child [OLPC]. By the end of 2005, she had completed the initial architecture, led the development of the first prototype, and signed up some of the world's largest manufacturers to produce the XO-1. By the end of 2007 she had led the laptop through development and into high volume mass production. At OLPC, Jepsen invented the laptop's sunlight-readable display technology and co-invented its ultra-low power management system, and transformed these inventions into high volume mass production.^{[17][18][19][20][21][22][23][24][25]}

Pixel Qi

In 2008, Jepsen started a for-profit company, Pixel Qi, to commercialize some of the technologies she invented at OLPC.^[26] The firm's business was based on the concept that the screen is the most critical component of any mobile device.^[27][28] It aimed to deliver high performance, low-power, sunlight-readable screens for mobile devices. The long-term vision of Pixel Qi was to create devices that never needed to be recharged by lowering the power consumption and using alternative power generation and battery technologies. Its screens became available in a few dozen commercial and specialized products with sunlight readability, and reduced screen power consumption (which typically accounts for about 90% of the power draw in a tablet, and 70% of the power draw on a standard cell phone.^[29]

Google X and virtual reality

Jepsen joined Google X in 2013. She advised and directed display and consumer electronic programs throughout Google.^[30] The Wall Street Journal reported that among her projects there she created Google Lego TV: displays composed of smaller screens that plug together like Legos to create vast, seamless images and "live walls" for wall size interaction, television, video conferencing and gaming, to virtual reality without having to wear anything on your face or body.^[31] She was also one of the first contributors in Google's "Solve for X" projects with her idea of "Imaging the Mind's Eye".^[32]

In February 2015, she joined Facebook as an executive for virtual reality.^[3]

Openwater

In 2016, she left Facebook and founded Openwater, a firm aiming to use infrared holography to make fMRI-type imaging inside the body practical, at the price level of consumer electronics and in wearable form factors.^[6][33] She gave a talk at 2018 TED on the technology behind the Openwater approach.^[34] At the IGNITION 2018 Conference, Jepsen further discussed the resolution progression of Openwater's MRI machines and the potential for the technology to make advancements in telepathy by allowing users to transmit thoughts and feelings electronically.^[35]

In a 2020 online call, Mary Lou mentioned that openwater devices are actively in the rapid prototyping phase with alpha kits expected August 2020. The Openwater website stated in 2020: "We are starting hospital studies on humans for use as a stroke detector at the end of 2020."^[36][37] As of 2020, the final devices were slated to come out sometime in 2021.