Expression of Concern: Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water.

Expression of concern for 'Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water' by Andrzej Dobek , , 2017, , 26749-26757, https://doi.org/10.1039/c7cp04061j.

Optical aberrations and modulation transfer function of a thermal lens for use in imaging.

The optical aberrations of the thermal lens formed in a liquid are reported for the first time as expressed in terms of the Zernike polynomials coefficients. Convection of the liquid in which the thermal lens is formed is shown to strongly modify the lens imaging properties, even for the case of vertical heating laser illumination, as studied herein. The time evolution of the optical properties of the thermal lens is investigated.

Thermal lens with passively tuned focal length formed in a photochromic material.

A new, to the best of our knowledge, way of tuning the focal length of a thermal lens is presented. The thermal lens is formed in a photochromic thermo-optical material, through illumination of the material by a heating laser beam of constant power. The tunability of the lens is achieved by changing the absorption coefficient of the thermo-optical material at the heating laser beam wavelength.

Multi-planar imaging using the thermal lensing effect.

The application of a thermal lens, formed by a laser beam, in the imaging of objects lying in three different planes is reported for the first time, to the best of our knowledge. The objects' planes are separated by a distance surpassing the depth-of-field of the imaging setup. It is the local formation of two thermal lenses near the intermediate image plane in a thermo-optical material that allows for the observation of two additional objects.

Multi-planar imaging using the thermal lensing effect.

The application of a thermal lens, formed by a laser beam, in the imaging of objects lying in three different planes is reported for the first time, to the best of our knowledge. The objects' planes are separated by a distance surpassing the depth-of-field of the imaging setup. It is the local formation of two thermal lenses near the intermediate image plane in a thermo-optical material that allows for the observation of two additional objects.