A four-dimensional (4D) general super-resolution imaging method (called PSF modulation method) was developed via modulation of an arbitrary point-spread-function (PSF) of an imaging system such as an ultrasound and optical system. The highest image resolution achievable will only be limited by the noises in the images. Theory, computer simulations, and experiments were presented.

A pulse-echo image of a super-resolution (0.65 mm versus a two-way diffraction-limited resolution of 2.65 mm, or 4.08-fold improvement) and 31-dB signal-to-noise ratio (SNR) was obtained with an ultrasound experiment using a 0.5-mm diameter modulator and 1.483-mm wavelength. Another ultrasound experiment shows that a wave source was imaged at a super-resolution (0.5 mm versus a one-way diffraction limited resolution of 3.63 mm, or 7.26-fold improvement) at about 30-dB SNR, using the same modulator size and wavelength.

In addition, a PSF-weighted super-resolution imaging method based on the PSF modulation method was developed. This method is easier to implement but may have some limitations. With a proper choice of a modulator (e.g., a quantum dot) and imaging system, nanoscale (a few nanometers) imaging is possible using the methods developed.Â