Nav: Home

Microscopic glass blowing used to make tiny optical lenses

June 25, 2019

WASHINGTON -- Inserting air into hot glass to form a bubble has been used to make glass objects since Roman times. In new work, researchers apply these same glass blowing principles on a microscopic scale to make specialized miniature cone-shaped lenses known as axicons.

Axicons are used to shape laser light in a way that is beneficial for optical drilling, imaging and creating optical traps for manipulating particles or cells. These lenses have been known for more than 60 years, but their fabrication, especially when small, is not easy.

"Our technique has the potential of producing robust miniature axicons in glass at a low cost, which could be used in miniaturized imaging systems for biomedical imaging applications, such as optical coherence tomography, or OCT," said research team member Nicolas Passilly from FEMTO-ST Institute in France.

In The Optical Society (OSA) journal Optics Letters, the researchers describe the new fabrication approach, which is based on the same processes used to make large numbers of photonic and electronic circuits in parallel on semiconductor wafers. The researchers used their approach to create glass axicons with diameters of 0.9 and 1.8 millimeters and showed that they successfully generated Bessel beams.

"Wafer-level microfabrication allows the axicons to be integrated into more complex microsystems created also at a wafer-level, leading to a system made of a wafer stack," said Passilly. "This type of integration comes with better optical alignments, high performance vacuum packaging and much lower-costs for the final systems because a large number can be processed simultaneously."

Creating a microlens

When used with a laser, axicons create a beam of light that begins as a Bessel-like beam -- a non-diffracting beam with maximum intensity on its axis -- and then turns into a hollow beam further away from the axicon. Bessel-like beams feature a depth of field that can be orders of magnitude larger than that of a beam focused by a traditional rounded lens with a similar diameter. The beam's high depth of field allows optical drills to reach deeper and creates higher quality OCT images. For optical tweezers, both the Bessel-like and hollow portions of the beam can be used to trap particles or cells.

Techniques traditionally used to make glass axicons can produce only one lens at a time. Although less expensive axicons can be made in polymer, these can't withstand high temperature processes such as wafer-level fabrication or be used in applications that require high levels of light power.

"Polymer axicons can't be used in optical drilling, for example, because the instantaneous light power is comparable to the power of a nuclear plant but with an extremely short duration," said Passilly.

Micro glass blowing has been previously used to make microlenses, but it usually involves gas expansion from a single reservoir. The researchers developed an axicon fabrication method that combines gas expansion from multiple reservoirs to produce the optical component's conical shape. The technique shapes the surface from underneath leaving a high-quality optical surface, unlike commonly used methods like etching transfer from a 3D mask that engrave the wafer from above.

To carry out the new micro glass blowing method, the researchers deposited silicon cavities in concentric rings that were then sealed with glass under atmospheric pressure. Placing the silicon and glass stack in a furnace caused gas trapped in the cavities to expand, creating ring-shaped bubbles. These bubbles pushed out the glass surface to form cone shapes and then the opposite side was polished away to leave only the shaped lenses.

"Although all the processes we used are standard for microfabrication, we applied these techniques in non-standard ways to make miniature glass axicons," said Passilly. "The technique could be applied to create other shapes, even ones without cylindrical symmetry."
The researchers plan to incorporate these optical components in OCT devices they are developing for cancer detection and other medical applications.

Paper: J. V. Carrión, J. Albero, M. Baranski, C. Gorecki, N. Passilly, "Microfabrication of axicons by glass blowing at a wafer-level," Opt. Lett., 44, 13, 3282-3285 (2019).

DOI: https://10.1364/OL.44.003282 .

About Optics Letters

Optics Letters offers rapid dissemination of new results in all areas of optics with short, original, peer-reviewed communications. Optics Letters covers the latest research in optical science, including optical measurements, optical components and devices, atmospheric optics, biomedical optics, Fourier optics, integrated optics, optical processing, optoelectronics, lasers, nonlinear optics, optical storage and holography, optical coherence, polarization, quantum electronics, ultrafast optical phenomena, photonic crystals and fiber optics.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit

Media Contact:

The Optical Society

Related Glass Articles:

On-demand glass is right around the corner
A research group coordinated by physicists of the University of Trento was able to probe internal stress in colloidal glasses, a crucial step to control the mechanical properties of glasses.
Glass from a 3D printer
ETH researchers used a 3D printing process to produce complex and highly porous glass objects.
Making glass more clear
Northwestern University researchers have developed an algorithm that makes it possible to design glassy materials with dynamic properties and predict their continually changing behaviors.
Researchers use 3D printer to print glass
For the first time, researchers have successfully 3D printed chalcogenide glass, a unique material used to make optical components that operate at mid-infrared wavelengths.
New family of glass good for lenses
A new composition of germanosilicate glass created by adding zinc oxide has properties good for lens applications, according to Penn State researchers.
In-depth insights into glass corrosion
Silicate glass has many applications, including the use as a nuclear waste form to immobilize radioactive elements from spent fuel.
Laser-fabricated crystals in glass are ferroelectric
For the first time, a team of researchers from Lehigh University, Oak Ridge National Laboratory, Lebanon Valley College and Corning Inc. has demonstrated that laser-generated crystals confined in glass retain controllable ferroelectric properties, key to creating faster, more efficient optical communication systems.
New research questions the 'Glass Cliff' and corroborates the persistent 'Glass Ceiling'
Are women more likely to be appointed to leadership positions in crisis situations when companies are struggling with declining profits?
A new path through the looking-glass
Exploring the mystery of the molecular handedness in nature, scientists have proposed a new experimental scheme to create custom-made mirror molecules for analysis.
Careful -- You are made of glass
Researcher Otger Campas and his group uncover how tissues and organs are sculpted during embryogenesis
More Glass News and Glass Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at