Dr. Leong-Chew Lim, Microfine Materials Technologies Pte Ltd Founder and CEO: “Collaboration with clients plays a key role in our technology and product development. Most of them are product and/or application oriented and are keen to push the boundary of current sonar technology.”

The thing about deep technology companies that survive for decades is they don’t get there by chasing headlines. They get there by solving problems that most people never see, in environments that punish shortcuts and reward only physics, patience, and nerve.

Microfine Materials Technologies Pte Ltd, better known in specialist circles as MMT, is one of those companies.

Founded in 1998 and headquartered at 192 Pandan Loop in Singapore, MMT has spent more than two decades quietly pushing the limits of advanced materials and devices, with a sharp focus on piezoelectric single crystals and the underwater transducer technologies they enable. Its founder and CEO, Dr. Leong-Chew Lim, did not set out to build a volume-driven manufacturing business. He set out to move the technology frontier, and then find the few customers in the world who cared enough to follow.

That decision has shaped everything MMT has become.

From Academic Spin-Off to Deep-Tech Specialist

MMT began as a technology spin-off from the National University of Singapore, founded by academic staff from the Department of Mechanical Engineering. In its early years, the company worked closely with Singapore’s Science and Technology Board, now A^*STAR, and with the country’s defense sector. The early mandate was ambitious and unforgiving: develop high-performance underwater transducers and arrays that could outperform existing solutions in real operational environments.

This was not contract R&D dressed up as innovation. It was foundational work in materials science, device physics, and manufacturing discipline, carried out by a small team that had to be both researchers and producers at the same time.

That dual role was not optional. As Dr. Lim puts it, pushing both R&D and production in high technology is never easy, especially for a small company. There are no shortcuts. MMT’s internal philosophy is blunt: be brave and assertive, make mistakes, learn fast, and move on quickly.

The result is a company culture where engineers multitask across crystal growth, device design, fabrication, testing, and iteration. Many have failed hard along the way. All of them, according to Lim, got back up stronger. Being small, in this case, turned out to be an advantage.

Betting Early On Piezoelectric Single Crystals

After experimenting with several functional ceramics, MMT made a defining choice. It would specialize in piezoelectric single crystal growth and applications, particularly for underwater transducers and arrays. The material at the center of this effort is lead zinc niobate–lead titanate, or PZN-PT.

Growing high-quality PZN-PT single crystals is not a trivial undertaking. MMT spent years refining a high-temperature flux growth technique, focusing on near-equilibrium conditions that improve crystal quality. The goal was not just to grow crystals, but to grow them cleanly, consistently, and at sizes that matter for real devices.

The results speak for themselves. The as-grown PZN-PT crystals exhibit well-defined growth facets, are flux- and crack-free, and are translucent when viewed against light. Over time, MMT progressed to growing larger crystals, reaching edge lengths of around 40 mm, as shown in Fig. (a).

Once diced and processed, these crystals deliver extremely high piezoelectric coefficients and electromechanical coupling factors, combined with low dielectric loss. That combination makes them particularly well suited for high-end transducer applications where efficiency, bandwidth, and sensitivity are not negotiable.

Some of the most critical aspects of MMT’s crystal growth setup and process control remain proprietary. They are deliberately absent from published papers and conference presentations. In an industry where reproducibility matters as much as peak performance, this discretion is strategic, not secretive.

Reinventing The Underwater Projector

Underwater transducers sit at the heart of modern sonar systems. Among the most widely used designs are low-to-mid frequency sound projectors based on tonpilz or piston architectures. These devices operate from a few kilohertz up to roughly 80 kHz and support applications ranging from underwater communication and bathymetry to imaging, target tracking, and obstacle avoidance.

Since the early 2000s, MMT has been experimenting with PZN-PT single crystals in underwater transducer designs. The company found that these crystals excel as piston-type projectors in the low-to-mid frequency range. Compared to conventional piezoceramic-based transducers, they offer wider bandwidth, competitive source levels, and significantly better energy efficiency.

These traits matter enormously for unmanned platforms, where size, weight, and power consumption directly constrain mission capability. When paired with high-frequency piezocomposite transducers, MMT’s low-frequency crystal-based projectors enable large-area, dual-frequency underwater imaging systems. These systems can image buried objects, scan several times the area of traditional approaches, and extract vibration signatures that help distinguish real targets from clutter.

The practical payoff is fewer false alarms and much higher object identification accuracy, even for sub-meter objects buried in sea mud.

The Overlooked Property That Changed Everything

One of the most consequential breakthroughs at MMT came from revisiting a property of PZN-PT that had been largely overlooked for decades: acoustic impedance.

For specific crystal cuts, particularly [011]-poled, 32-transverse-extension mode PZN-PT with the [100] direction as the active axis, acoustic impedance can be as low as 5 to 8 MRayls. Water, by comparison, sits at about 1.5 MRayls. This is dramatically closer than conventional piezoceramics or many other single crystals.

This acoustic matching made something possible for the first time. MMT could design transmission-line-like underwater transducers that are acoustically matched to water at low-to-mid frequencies, without the size and inefficiency penalties of traditional designs.

The result is the “underwater sound emitting dot,” or UWSED transducer, shown in Fig. (b). These devices have footprints of just 12 to 15 diameter, yet each can generate sound pressure levels of 175 to 180 dB re 1 µPa at 1 meter when driven at 50 to 80 Vrms in shallow water.

That output rivals conventional tonpilz transducers made from PZT ceramics or single crystals that are many times larger and significantly more power-hungry. Even more importantly, UWSED transducers maintain footprints smaller than half a wavelength in water, even when operating in second or third resonance modes. Each mode typically offers relative bandwidths exceeding 30 percent.

This combination of size, bandwidth, and efficiency changes what sonar designers can realistically build.

New Sonar Architectures, Finally Feasible

With UWSED technology, sonar arrays that were previously impractical or impossible become achievable.

MMT has demonstrated and continues to develop wide-beam, high-source-level, low-to-mid frequency fishery sonars, as shown in Fig. (c). The same technology supports high-element-density arrays with exceptional maneuverability, illustrated in Fig. (d).

Because of the compact footprint and broadband behavior, UWSED transducers also enable ultra-broadband devices exceeding one octave in bandwidth and embedded multi-frequency sonar arrays, shown in Fig. (e). These architectures support advanced imaging and sensing modes without the traditional penalties of size and complexity.

Other applications include miniaturized parametric arrays with much higher power efficiency,  and even the prospect of compact low-frequency arrays operating at just a few kilohertz. For naval, commercial, and scientific users alike, this opens design space that simply did not exist with legacy transducer technologies.

MMT is actively working with several world-leading technology partners to turn these concepts into deployed systems.

Beyond Projectors: Sensors And Actuators

The same PZN-PT single crystals that underpin MMT’s projector technology also excel in sensing and actuation roles.

In hydrophones, where sensitivity and size often trade off against each other, MMT uses PZN-PT to fabricate miniature hydrophones with receiving sensitivities of –194 dB or better. These devices are well suited to dense arrays and compact platforms.

Shear-mode PZN-PT crystal cuts, with shear piezoelectric coefficients around 4500 pC/N, enable compact, low-frequency accelerometer-based acoustic vector sensors. Compared to piezoceramic counterparts, these sensors offer unmatched sensitivity, expanding what is possible in directionally aware underwater sensing.

When grown with high-purity charges under near-equilibrium conditions, certain PZN-PT compositions exhibit dielectric losses below 0.1 percent. MMT uses these crystals to build near-hysteresis-free, high-fidelity displacement actuators for precision positioning and motion control. In these systems, performance is high enough that control electronics can remain relatively simple.

Engineering For The Next Leap

MMT has not stopped at its current generation of materials and devices. In support of ongoing R&D, the company is developing new PZN-PT compositions with several goals in mind.

One is increasing transducer and array source levels by at least 6 dB on a size-for-size basis, through higher coercive field strengths and improved mechanical quality factors. Another is pushing operating temperatures to 150°C or higher, expanding the range of environments these devices can tolerate.

These developments, along with derivative devices, will be announced in due course.

Separately, MMT also fabricates low-noise piezocomposite transducers for downhole structural inspection in the oil and gas industry. These products are distributed globally by a Singapore-based technology leader, underscoring MMT’s role as an enabling partner rather than a mass-market brand.

Collaboration As Strategy

Collaboration sits at the core of how MMT operates. Many of its customers are product- and application-driven organizations intent on pushing the boundaries of sonar technology. These partners understand that meaningful advances take time, iteration, and trust.

MMT chooses collaborators carefully. While it publishes less today than in its earlier, more exploratory years, it encourages partners to publish results when appropriate. The company attends fewer conferences, but only those that matter. Dr. Lim still travels frequently, though increasingly for business meetings rather than academic presentations.

The model is selective, focused, and unapologetically deep-tech.

A Quiet Force In A Noisy World

MMT does not court publicity, and it does not pretend its work is simple. What it offers instead is rare: a vertically integrated capability spanning advanced materials growth, device engineering, and real-world deployment in some of the harshest environments imaginable.

For high-end underwater transducer and sonar system developers, precision motion control designers, and high-technology investors looking beyond software cycles and hype curves, Microfine Materials Technologies represents a different kind of opportunity.

It is a company built on physics that cannot be faked, products that must perform, and a belief that real innovation still comes from those willing to take the hard road, learn fast, and keep going.

In underwater acoustics and precision devices, that quiet persistence may be exactly what reshapes the field next.

Dr. Leong-Chew Lim, Founder & CEO