Changing the orientation of a lens can indeed alter the basis for measurement of photon polarization. To understand this, we need to consider the concept of photon polarization and the role of a lens in manipulating it.
Photon polarization refers to the orientation of the electric field vector associated with a photon. It can be described using different bases, such as the horizontal-vertical (HV) basis or the diagonal-antidiagonal (DA) basis. In the HV basis, the polarization state of a photon is represented as a linear combination of horizontal and vertical polarization states. In the DA basis, the polarization state is represented as a linear combination of diagonal and antidiagonal polarization states.
A lens is an optical device that can focus or collimate light. It has the ability to alter the direction and orientation of light rays passing through it. When a photon passes through a lens, its polarization state can be affected depending on the orientation of the lens.
Let's consider an example to illustrate this. Suppose we have a horizontally polarized photon incident on a lens. If the lens is oriented such that its optical axis is parallel to the horizontal polarization direction, the lens will not have any effect on the polarization state of the photon. However, if the lens is rotated by 90 degrees, such that its optical axis is now perpendicular to the horizontal polarization direction, the lens will transform the horizontal polarization state into a vertical polarization state. This change in orientation of the lens has altered the basis for measurement of photon polarization from HV to DA.
In general, changing the orientation of a lens can lead to a transformation of the polarization basis. This is because the lens can introduce a phase shift between different polarization components, effectively rotating the polarization state of the photon. The amount of rotation depends on the angle of rotation of the lens and the specific design of the lens.
It is worth noting that the basis for measurement of photon polarization is not fixed and can be chosen based on experimental requirements. By changing the orientation of a lens, we can effectively change the basis for measurement, allowing us to explore different aspects of photon polarization and perform various quantum information tasks, such as quantum state tomography or quantum communication protocols.
Changing the orientation of a lens can alter the basis for measurement of photon polarization by introducing a rotation to the polarization state of the photon. This rotation depends on the angle of rotation of the lens and can lead to a transformation between different polarization bases, such as HV and DA.
Other recent questions and answers regarding Examination review:
- In the context of interposing a lens at a 45-degree angle between two other lenses, what is the overall effect on the polarization of a photon?
- How does the probability of transmission through a polarizing filter depend on the angle between the polarization and the orientation of the filter?
- How does a polarizing filter or lens measure the polarization of a qubit?
- What is the relationship between the orientation of the electrical field oscillations and the polarization state of a photon?

