Key Takeaways:
- Avantier designed a custom objective lens for a university department, meeting strict criteria for trapping and imaging single atoms.
- The lens features a large numerical aperture (NA) of 0.5, optimal for high-resolution imaging at 780 nm-1064 nm wavelengths.
- Its 15mm working distance accommodates two lasers without interference, which is crucial for achieving accurate atom manipulation.
- Advanced engineering ensured diffraction-limited performance and minimized chromatic aberrations.
- Using active alignment methods, Avantier achieved precise optical performance and a focal shift of less than 1 µm across all wavelengths.
- Testing confirmed a resolution of 1.45μm, close to the theoretical limit of 1.26μm, demonstrating the lens’s exceptional performance in atomic capture.
Introduction
Avantier received a request from a university’s Applied Physics department to design a long working distance large numerical aperture custom objective. Our highly knowledgeable and experienced engineers were able to design and utilize state-of-the-art technology to develop a single atom trapping and imaging system. In this system, two lasers are shot through cover glass, impacting a single atom. The objective lens not only had high transmission but also the diffraction limited performance over the full field.
Wavelength |
780 nm-1064 nm |
Working distance |
15mm: air+5mm vacuum+4mm |
NA |
0.5 |
Focal length |
10mm |
Dimension |
Φ38mm*80mm |
Conjugate distance |
Infinity |
Typical requirements for the objective lens used for trapping and imaging single atoms:
- Having large NA for the high imaging resolution and receiving enough energy in imaging wavelength.
- Having long working distance for two lasers, incident angle 45 degree and high NA, so that the use of two lasers wouldn’t interfere with the mechanical diameter.
- Delivering diffraction limited performance for all imaging wavelengths at the fixed focal plane over the entire field of view.
- Minimizing chromatic shifts/aberrations at all wavelengths
Custom objective lens example
Objective lenses trap atoms at wavelengths of 780 nm and 852 nm and produce diffraction limited performance at wavelengths between 780 nm and 1064 nm. The figures below show the MTF plot at all wavelengths.
The objective lens is designed to have a total focal shift of less than 1 µm for all wavelengths. The chromatic focal shift is shown in the following figure.
The lens design spot is smaller than the Airy spot radius, showing that the lens has reached the diffraction limit.
The figure above is a photo of the manufactured objective lens. The active alignment method was used to eliminate the effect of optical fabrication errors, spherical aberration, and coma, thereby enhancing the len’s optical performance
The lens test equipment was developed in-house, and the equipment model is illustrated in the figure below. Testing principles such as the Point Spread Function (PSF) diagram and the position of the energy cross-section, are utilized. Through calibration testing at 20% of the peak energy position, the resolution can be calculated. Following testing and analysis, the resolution was determined to be 1.45μm, which is close to the theoretical value of 1.26μm. It can be considered that the lens has reached the theoretical design value and has successfully completed the atomic capture.
Conclusion
Avantier Inc. has delivered a remarkable custom objective lens tailored for trapping and imaging single atoms, meeting stringent specifications with exemplary performance. Through innovative design and advanced engineering, the lens showcases a large numerical aperture (NA) of 0.5, ensuring high-resolution imaging and optimal energy reception across the desired wavelengths of 780 nm and 852 nm. Its elongated working distance of 15 mm, adaptable to both air and vacuum environments, allows for unimpeded laser angles crucial for precise atomic manipulation.
In essence, Avantier Inc.’s custom objective lens stands as a testament to ingenuity and precision, successfully meeting the demanding requirements of single atom trapping and imaging, and thus offering unparalleled performance in atomic capture endeavors.
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