The wavelength of a photon is determined by its frequency through the equation c = λf, where c is the speed of light, λ is the wavelength, and f is the frequency. Since the speed of light is constant in a vacuum, if you want to increase the wavelength of a photon, you need to decrease its frequency.
However, it's important to note that the frequency of a photon is directly related to its energy. According to the equation E = hf, where E is the energy of the photon and h is Planck's constant, the energy of a photon is directly proportional to its frequency. Higher-frequency photons have higher energy, while lower-frequency photons have lower energy.
In practical terms, you cannot directly control the wavelength or frequency of a photon. These properties are intrinsic to the specific type of electromagnetic radiation or light. For example, visible light photons have a range of wavelengths and frequencies associated with different colors. If you want to interact with photons of different wavelengths or frequencies, you can use various materials or devices like prisms, diffraction gratings, or filters to manipulate or select specific ranges of wavelengths or frequencies.