We analyze spatial characteristics of the four-wave radiation converter in a two-component medium consisting of a transparent liquid and nanoparticles with allowance for the gravity force. It is shown that allowing for the gravity force acting on nanoparticles affects significantly the efficiency of conversion of low spatial frequencies. Three ranges of effective nanoparticle masses (small, intermediate, and large), for which various types of spatial spectra of an object wave are observed, are distinguished. In the first range, a four-wave radiation converter filters high spatial frequencies of the signal wave. The relationship between the half-bandwidth of spatial frequencies cut out by the four-wave radiation converter and the effective mass of one nanoparticle is established. For the second range, it is shown that a frequency band, the center of which is shifted to the higher frequencies and whose width decreases with increasing effective nanoparticle mass, is cut out from the spatial-spectrum modulus of the signal wave. In the third range, the four-wave radiation converter filters low spatial frequencies with a half-bandwidth that increases with increasing nanoparticle mass.

我们分析了四波辐射转换器在由透明液体和纳米颗粒组成的双组分介质中的空间特性，并考虑了重力。结果表明，允许作用在纳米颗粒上的重力会显着影响低空间频率的转换效率。有效纳米粒子质量的三个范围（小、中和大）被区分，对于这些范围，可以观察到物体波的各种类型的空间光谱。在第一个范围内，四波辐射转换器过滤信号波的高空间频率。建立了四波辐射转换器截取的空间频率的半带宽与一个纳米粒子的有效质量之间的关系。对于第二个范围，显示了一个频带，从信号波的空间频谱模量中切出其中心移至较高频率并且其宽度随着有效纳米颗粒质量的增加而减小。在第三个范围内，四波辐射转换器过滤低空间频率，其半带宽随着纳米粒子质量的增加而增加。