Meet Samuel Li from Samsung and SJL Instruments

Meet Samuel Li, a recent master's graduate, Senior Modeling Engineer at Samsung Semiconductor, and founder of ultrafast oscilloscope company SJL Instruments in San Jose, CA. 

May 23, 2025

Introduce yourself! Where are you from, and where are you living and working now? 

SL: Hi - I’m Sam! I grew up about half-and-half in Florida and Ontario, Canada. I recently completed my MA in physics at Princeton University, where I worked on ultracold molecular tweezer arrays. I’ve since moved to San Jose, California, where I work at Samsung Semiconductor as an applied physics researcher, and run a business selling low-cost, ultrafast oscilloscopes. 

Tell us about your job at Samsung! What is your current role there? Generally, what do you do? What does your day-to-day look like?

SL: I’m a Senior Modeling Engineer at Samsung Semiconductor. Almost nobody has heard of this role. Broadly speaking, I develop both rigorous and empirical physics-based models of the various semiconductor manufacturing steps. I spend most of my time writing simulations (usually deriving and/or solving PDEs), thinking about the results, and validating against data. It’s a workflow that I’m sure is familiar to many of your readers.

What do you like most about your current role at Samsung?

SL: Due to how many steps are involved in semiconductor manufacturing, you can essentially pick anything on the spectrum between experimental physics and theoretical physics. Some people analyze electron microscope data, while others are experts in density functional theory. I’ve even dipped a bit into conformal field theory.

In my mind, there’s a distinction between a “software job,” where the end product is software, and a job which involves writing software. The Modeling Engineer role falls in the second category. It’s primarily a physics research role.

The problems are interesting and difficult. Perhaps more importantly, even a very small improvement gets multiplied by the billions of semiconductor devices produced. Your impact is immediate, and benefits everyday people.

You’re also an entrepreneur. Can you introduce your company, SJL Instruments?

SL: SJL Instruments has one goal: lower the barrier-to-entry for multi-GHz, picosecond-scale measurements. Our first product, the GigaWave 6000-series sampling oscilloscope, has a bandwidth of 6 GHz, with true (not interpolated) timing precision measured in fractions of a picosecond. It’s also vastly cheaper than any comparable option on the market today, thanks to a novel acquisition technique (CDF sampling).

The GigaWave has been shipping for nearly two years now, with customers in nearly 20 countries. A lot of applications are in photonics and quantum computing - anyone who needs to measure really fast pulses. We also supply customized boards to OEMs, for integration into larger systems.

We’re actively developing new products with a similar goal - ultra-high bandwidth at ultra-low prices, made possible by genuinely new architectures.

What made you decide to start SJL Instruments? What is it like to manage your business while also working a full time job?

SL: I started SJL Instruments entirely by accident. Long story short, I designed the GigaWave for fun, and only later realized it could be useful to other people. After doing a bit of market research, it made no sense not to start a company.

A huge benefit of running your own business is the flexibility. I can assemble, test, and pre-package a batch of oscilloscopes on the weekend, or whenever I find time. During the week, I only need to respond to customers and ship out orders.

Of course, the R&D for a new product takes a very long time, but after a product is launched and any early problems are ironed out, the day-to-day time commitment is minimal.

What made you decide to leave your graduate program with a masters? What advice would you give to others considering doing the same?

SL: I left because I no longer wished to pursue an academic career. It was a simple decision, but not easy, and one that I feel many are afraid to make. My advisor was very understanding, and we parted on good terms.

I think it’s important to understand that academia is not a way to opt-out of finding a job — it just delays the decision. Think carefully and honestly about why you are doing a PhD. If it really does align with your goals, that’s great! If not, there should be no shame or stigma in leaving as soon as it becomes clear. Waiting longer simply makes the decision harder.

How did you find out about your job at Samsung?

SL: I heard about the job by accident, through a high-school friend who ended up in a similar role by accident. “Modeling Engineer” is not a position that most people have heard of — we’re not exactly flooded with applications, and are always on the lookout for people with strong physics backgrounds. Feel free to reach out!

What makes for a successful career in physics?

SL: A successful career is one that you’re happy with. It may be in academia, or it may not. In my opinion, the only algorithm that guarantees this is to leave if you are unhappy, then repeat. The best role for you might be one you’ve never heard of. Don’t be afraid to take opportunities when they pop up.

Do you have any advice for people thinking of starting their own companies?

SL: Many people decide to start a company, then try to think of ideas. This is the wrong way to do it.

When you encounter a potential idea, take a second to think about the economics of turning it into a business. Who are the customers? What are their existing options? Does your idea actually solve a real problem?

Almost every time, the idea will be barely profitable or already established. When, by chance, you run into a great idea, you will know immediately.

What excites you about quantum science?

SL: I’m excited about the massive computational power that could in principle be exploited, given precise enough control over quantum systems. This is not necessarily quantum computing — even classical transistors are running into the quantum regime, where we need to fully understand quantum effects to model them properly.

Perhaps some clever arrangement of atoms could act as a smaller, or faster, or more energy-efficient transistor. There’s roughly a factor of a billion left before classical computers hit the Landauer limit. Precise quantum control is also one of the few pathways that could conceivably enable reversible (i.e. zero-energy) computing.