## 3 Results and Discussion  
### The Radiation Diffraction on the Structure  
Figure 2 presents the calculation results of the irradiating light diffraction over the analyzed structure (AS). We consider a monochromatic plane electromagnetic wave, a normal incident on the AS in the negative direction of the \(y\) axis. This wave with the complex vector of the electric field \(E_{0}\) is linearly polarized along the \(x\) axis. Here are the normalized distributions of the squared absolute value of the electric vector \(|E|^{2}/|E_{0}|^{2}\), where \(E=Es+E_{0}\) is the complex vector of the total electric field, that is, the sum of the complex vectors of the scattered \(Es\) and the given irradiating \(E_{0}\) fields. These distributions, calculated at a wavelength of the illuminating beam of 500 nm and 700 nm, are presented in the fragments of Figure 2a,b, respectively. It can be seen that the field distributions have the form of a series of bands with the minimum and maximum values alternating in the vertical direction with the period close to \(\lambda/2\). These distributions have a pronounced interference structure characteristic of the standing waves with the alternating nodes and antinodes. Thus, the field distribution is largely determined by the interference of the waves, which are incident and reflected from the blade and the gate. With a change in \(\lambda\), the location of the interference fringes changes. As a result, the tip of the blade may be in the region of low or high field values. This leads to migration of the areas of increased field absorption in the area of the tip of the blade-emitter, which is analyzed in the next section. Spectral and Spatial Dependences of Amplification of the Optical and Electrostatic Fields on the Blade of the Structure  
The efficiency of the photosensor is largely determined by the absorption intensity of radiation by its cathode. It is desirable to maximize this intensity and, consequently, the number of photoexcited (hot) electrons [21; 22; 23; 24]. The local intensity value of radiation absorption is determined by the following equation [24]:  
\[Q=0.25\cdot\
u\cdot\varepsilon^{-}|E|^{2}, \tag{2}\]  
where \(\
u\) is the radiation frequency and \(\varepsilon^{-}\) is the imaginary part of the dielectric function of the absorbing material. The calculation of the local intensity distribution of radiation absorption is actually reduced to the calculation of the squared modulus distribution of the electric field vector \(|E|^{2}\) in the absorbing material. The results of the given calculation are presented in Figure 3.  
The calculation results of the two-dimensional distribution of the function \(|E|^{2}/|E_{0}|^{2}\) inside the nanoscale tip of the molybdenum blade and outside in the vicinity of the tip, that is, in the vacuum, are presented in this figure. We can see a high degree of field localization in molybdenum in the  
Figure 2: Normalized distributions of the squared modulus of the complex total electric field vector \(|E|^{2}/|E_{0}|^{2}\) in the analyzed structure, where \(E_{0}\) is the complex electric field vector of the illuminating beam at the wavelength of (**a**) 500 nm and (**b**) 700 nm. near-surface layer, with the depth of several nanometers. In addition, there is a heterogeneity of the near-surface field in the orthogonal direction along the perimeter of the forming blade. Moreover, the location of these field inhomogeneities varies depending on the wavelength of the incident radiation. A similar pattern is observed near the tip of the emitter in the vacuum. The maxima of the field change their position along the perimeter of the forming blade with a change in the wavelength of the incident radiation. Thus, the spectral dependence of the areas of increased field absorption location in the emitter blade is obvious, which should be taken into account when choosing the operation modes of the given type of photosensors with increased efficiency.